Before starting Bitcoin investment you must have prepared yourself for period of time financially because you know what it will take a and how long for that investment to mature either long term for 6-10 years or short term for monthly /weekly, and so your source of income should be enormous on other to meet up your other demands and need .
Having a fixed amount set aside from your monthly income is not a bad idea ,so that it will not affect your DCA strategy used in investing.
Let's take for instance in building a house ,you just don't stand up one day and say you want to build without planning for it and knowing how much to set aside for the project, is either you have been saving for it or have already gotten the resources for the building and how long it will take for the completion that will make your target and budget easier for you to pursue and it will be easily achieved and you will build it according to your capacity . The same way goes in investing Bitcoin you do invest above what you can afford .
But remember investing what you can afford is the best either 5-10% or 30% and more.
Indeed, this is a real example if we look at the life of building an average house, which we rarely see unless it is someone who has enough funds and is an established entrepreneur.
Well, inspired by that too. Maybe when it comes to investing in BTC, people are rarely able to buy at once, for example 1 BTC. Well, with the DCA method this is another way to get there. although little by little and the times are also supportive for now it is still cheap because BTC is still on its way to a new ATH. Possible.
I don't see buying bitcoin as the same thing with building a house. This is because when you want to build a house, you must have a huge amount of money to start with, but bitcoin doesn't need that just a small percentage from your income will get you started as long as it doesn't affect other budgets for the monthly. With some amount, you can use it to continue buying over a long period of time to increase your bitcoin portfolio.
To build a house is very expensive and needs experts in various areas, but bitcoin investment doesn't need a third party, as long as you know how to save some money from your income for something important that you want to achieve. You can also be investing that money into bitcoin and assume that the important thing you want to have is to reach your bitcoin target in a given timeline, let's say from four years and above. This is why the DCA strategy is recommended and the best for everyone but more in favour of the the low income earners who cannot lump sum. The rich has also admire this strategy and those of them that have the passion to keep on buying bitcoin are using the DCA method too.