Besides cashflow you need to consider how much bitcoin you have already accumulated (if that is part of your investment portfolio), your other investments besides bitcoin (including cash reserves), your view of bitcoin as compared with other investments, timeline, risk tolerance, and your time, skills, goals (investment/lifestyle targets , which includes figuring out the extent that you are in BTC accumulation, maintenance or liquidation stage) and your abilities to strategize, plan, research and learn along the way including tweaking strategies from time to time to consider trading, reallocating, use of leverage and/or financial instruments.
I always have cash reserves which I plan to do for dollar cost averaging but a more important plan is for emergency. The cash reserve for emergency will be intact, won't change if I won't suddenly become rich. The cash reserve for dollar cost averaging will be changed a lot with my new cash in from my income and money I have after my monthly expenses.
I can continue or postpone my dollar cost averaging, it is not a big issue but I try to do it as much and as most regular as possible.
I see the cash reserve for emergency is very important because if I use all my cash for investment, if I urgently need cash for emergency, I will have to sell my bitcoin at price I don't want to sell. It can be price that gives me small profit but worse give me big loss.