[edited out]
Through market analysis you will gain extensive knowledge which will make you a bigger investor in the future so you need to analyze the market before investing in Bitcoin. Even if you are a new investor you should plan your future based on past price analysis. Suppose you invest in Bitcoin, do you keep your capital on blind faith, which you should not. You will determine your strategy sophisticatedly through market study strengthen your earning base accumulation Bitcoin from disposable income. It is true that Bitcoin is still in its infancy and has already become a store of huge value. You need to consider why you should study the market. The answer to the question is that suppose you buy Bitcoin with the equivalent of $5000, before doing so, you need to analyze why the value of Bitcoin may increase or decrease in the future. Through each analysis, you will be able to imagine whether you should invest in one lump sum or divide it into several slots. Or you can accumulation Bitcoin continuously every week/month from discretionary income. Analysis of all the information about the Bitcoin market.
If you are new to bitcoin, and you already know that you have $5k that you want to invest into bitcoin to get started, and there is no need for deep analysis and/or waiting. Sure, you could be new to bitcoin yet you still don't know very much about bitcoin beyond some superficial ideas that might relate to looking at BTC's price history and maybe some articles that you read about bitcoin. At the same time, if you had come to the conclusion that you want to invest $5k into bitcoin, there is no reason that you should not just take 1/3 of the $5k ($1,666) that you have and buy bitcoin with it right away, and then consider whether you want to DCA and/or buy on dip with the other 2/3 ($3,333) that you have available.
When first getting started in bitcoin, there tends to be no need to try to time any dips, yet sure, if you might feel that you are more comfortable to dedicate some portion of the $5k that you have available towards buying potential dips that might happen (or might not), you surely have that luxury when you have money available.. yet a lot of beginners get too much caught up presuming that BTC prices are going to dip, which truly may not end up being the case, but if you have already put some money into bitcoin, then there is nothing wrong with getting more comfort into dividing your funds up, especially if you might believe that it gives you more psychological comfort (even though you can appreciate and recognize that in the short term, the BTC price can go in either direction, and there is no real way to measure which way the BTC price might go in the short term) - except maybe perhaps if you can identify longer waves, you might consider that during bull periods of the 4-year cycle then the BTC price is more inclined towards up and during bear periods it is more inclined towards down, yet that information still might not help a bitcoin newbie very much since, maybe it would be better that the bitcoin newbie just establish some kind of a budget to invest into bitcoin every week no matter the BTC price for at least a whole cycle, if not longer and perhaps, attempt to figure out if at some later point, such newbie bitcoin want to adjust his BTC accumulation strategy after he had spent a decent amount of time accumulating bitcoin.
If someone is a real newbie to investing (not just a newbie to bitcoin), then there should be some recognition that building an investment portfolio will frequently take 10 years or longer even though surely any person who is able to start with some abilities to lump sum invest may well be a little more advantaged over many folks who are frequently in a better position to just start investing on a regular basis from extra value in their income (taking from their weekly-ish discretionary income).
Even if you have $5k to start your investment, you can also consider what is your projected income and expenses over the next 3-6 months, and take that discretionary income into account in regards to the extent to which you might have money from your projected income that you can also fold into bitcoin investing into the future. For example, if you already know that you have $100 per week that comes from your income that you will be able to invest into bitcoin into the future 6 months or more, then you would consider the $5k that you have to be equivalent to about how much you might be able to invest into bitcoin over a year's time. Surely normal people will usually have some irregularities in their cashflows (income/expenses) that they might not completely know in advance, so those irregularities might allow for more or for less abilities to invest into bitcoin into the future.
Another thing that we might be presuming about the guy with $5k is that he already has an emergency fund that is already equivalent of at least 3 months of income (or at least expenses), and if he does not have an emergency fund that is at least 3 months of expenses, then he may need to consider putting some of his available $5k into that.. . yet there is no reason to necessarily prioritize the emergency fund over investing into bitcoin, so he could choose to grow his emergency fund and the size of his bitcoin investment at a similar pace until the emergency fund gets to the size of at least 3 months of income.
Using the expression extra cash, left over cash, or discretionary income would have been more better than using excess money in your expression which sounds more ambiguous to me, it sounds more like one needs more than enough prior to starting bitcon investment since anyone can come in with as little as what can be called left over money when our basic needs has been taken care of.
For me there is no cash that is left over cash because human needs are unsatisfiable. The cash you call left over is only that you have not really though of investing it or use it for a particular need. What people call leftover cash can quickly be inverted to Bitcoin andnsabe for the future because there is a saying that 'the money you save today will save you tomorrow' this is why I have chosen to save my own money in Bitcoin. Investing in bitcoin is something you need to have a set goal. First you need to have a source of income and set outside the cash for your basic needs and also set outside emergency fund so that you will have a relaxed mind as you will be able to keep your investment growing. As I was told in this forum that using DCA is the best method of growing your bitcoin investment which have been working for me and also to start quickly as possible as procrastination may lead to had I know.
You are not saving your money in bitcoin rather you are investing it and the money you use in investing into Bitcoin is your discretionary income which is also your leftover fund, if you are not investing with your leftover fund you will definitely sell your bitcoin in a short while because the money which you use to invest into Bitcoin is the money you will be needing soon that's why we are advised to use our leftover fund to invest in bitcoin that's the money we won't be using in the next 4-10 or more.
Someone can actually save money in Bitcoin, it is just a mindset thing. There are people that consider buying Bitcoin as saving their money in Bitcoin rather than keeping them in the bank to battle inflation that is increasing on daily basis. To such person, even if Bitcoin did not make x10 0r x1000 they are not worried because they know that over time the price will at least come back up and they will not have their money depleted. This is logical because I know a lot of people who put their money in fixed deposit only to have their money depleted in value to as high as 40% even though they seems to have earned interest in such deal. In other words, the purchasing power of their capital together with the interest becomes lower than their capital after keeping the money for some years. For this reason, someone can decide to save the money in Bitcoin instead of fiat.
I doubt that it makes much difference if we use the word "save" or we use the word "invest" when it comes to bitcoin. These words have similar meanings, even though surely it is more important that we might consider how our considerations might be different if we might come to realize that all fiats tend to go down in value with the passage of time, and some fiats go down worse than others. Surely bitcoin is not guaranteed to go up or to go down, yet any of us who study into bitcoin and can recognize and appreciate bitcoin's investment thesis, then we can also recognize that bitcoin is likely amongst the most sound money ever known to man (likely the most sound money ever invented/discovered), so the inability to debase bitcoin by creating more units makes it a way better place to put value, whether you refer to that activity as investing or saving.
Many of us also likely realize that there are various kinds of underlying battles in regards to bitcoin, that sovereign nations, financial institutions and/or status quo rich might not always be saying out loud, and so yeah, sometimes there is seeming friendliness to bitcoin, and other times there are a variety of attempts to place controls on bitcoin, and so such battles are likely also reflected in bitcoin's volatility as it continues to be adopted, which is likely going to continue to take time and continue to have a lot of misinformation and disinformation, including that many normies have hardly any clue regarding what bitcoin is or what it represents, even though we also witness some very rich folks starting their own journeys to stock up on bitcoin, whether they are doing it overtly or covertly and some of the more public institutions have obligations to disclose their financial activities (including the ways that they might be gaining price exposure to bitcoin).
Whether you call your own activities as investing or saving is likely less important than the various measures that you are attempting to take in order to make sure that you are continuing to build your bitcoin stash as aggressively that you are able to without overly putting your bitcoin at risk...and there are going to continue to be folks who continue to make a lot of mistakes regarding bitcoin by failing/refusing to sufficiently and/or adequately accumulate it, and also to end up selling too much too soon (or otherwise losing their bitcoin), and screwing themselves.