It solely the decision of any investor to decide how much he is willing to invest in Bitcoin or any other asset. Bitcoin have high return proportional to the investors Level of Accumulation of it (stash) which is guaranteed in a long run, it simply a matter of discipline, if the investor is disciplined there is nothing that can shift his focus.
Bitcoin's price performance is not guaranteed in the long run to go up - even though many folks (including myself) invest into bitcoin based on presumptions that it is more likely than not to go up in the long run... so each of us needs to establish our position size in accordance with a variety of factors, including the factor that BTC's price is not guaranteed to go up.
Sometimes I do come across people talking vehemently about their investments being guaranteed in the long run forgetting to know that uncertainty do happen even though we are making speculations but the most reasons why we make good speculations about the asset we invested on is simply because we need to be positive and hope for the best in our investments but that shouldn't mean we should be too affirmative in our analysis and speculations because so far as bitcoin is concerned, there are factors that leads to projection of it's price, so if those factors don't appear in the actual direction then it will be difficult to maintain same irrational mindset or beliefs.
Basically being realistic and positive about investing in Bitcoin will motivate you to accumulate a much larger stack.You may be accumulating a part of the worldly wealth in Bitcoin and it has to pull up to a point and keep your tongue wet. I have seen some investors convert some of their assets into Bitcoin and they choose to build another asset there. And there is a reflection of their confidence. You can follow them if you have confidence and positive attitude. I think a positive attitude is absolutely essential in investing and without it you will not be able to accumulate your stack freely. You should decide to choose your cushion amount of assets in depositing Bitcoin because you are holding it and the rest of the assets are financial security.
Selling your assets to buy Bitcoin is not advisable except they are liability that are in form of assets and they are not productive or bringing any returns or proceeds for you at the end of the day but if they are business assets like lease office equipments such as heavy duties, caterpillars, construction equipments and lifting equipments these are very good assets because they give you good proceeds so you can't sell such assets to buy Bitcoin but you can use the proceeds to invest in bitcoin, the only time you can consider selling such assets to buy Bitcoin is in a case where they start malfunctioning or getting old such that the cost of maintenance may be higher than the income they generate for you.
Selling your assets to buy Bitcoin is not bad if the cost of maintenance of those assets becomes too much but never use because you are inquisitive to buy Bitcoin and sell a valuable asset even though Bitcoin is also a valuable asset because just like what I was emphasizing before you quoted me than even though we are hopeful that our investments in Bitcoin are secured but let us not also forget that there are unforseen events that are likely to occur if the forces that keeps the market going are not in place so we should be mindful and thoughtful of the decisions we take when making investments.
Currently, with the uptrend in bitcoin price since it was created till now and the presumption that the odds of bitcoin price moving uptrend overtime is higher than downtrend selling an assest to put the value in bitcoin is not a bad idea. This is because currently bitcoin is one of the best assest, or let me say that the best assest to invest in that will give you a greater profit overtime than any existing assets.
The construction equipment that you are talking about will only be useful if it is hired out by a company and the day that it is not hired, there will be no funds from there. By the way do you know how much it is to acquire those construction equipment that you mentioned above. If you put all those money into bitcoin DCAing and buying at the dip regularly for just 4 years, do you know how much you will get in profit for 8 years which is additional two circles. Those equipment will worn out in future and become liability to you. But your bitcoin investment can never be a liability because it is a store of value and serves as an investment at the same time.
Just my thoughts.