It seems hard for me to read from the beginning of this thread because of the plenty of pages in this thread, but i adopt a strategy of reading from the current pages of this thread, and i have been doing that for some days now. It has helped me understand how significant and reliable dollar cost averaging is when accumulating bitcoin. If i receive my monthly salary by the end of this month and if i solve my monthly expenses, I will use the remaining money to start accumulating bitcoin.
From experience I've observed that waiting explicitly for what is left over after taking care of all expenses before investing into Bitcoin is an evidence of improper planning. You would end up servicing even less important things and at the end nothing might really be leftover to invest into Bitcoin.
It's important you take into consideration your likely expenses for the month, calculate it by yourself with acceptable tolerance to entertain price spikes, dedicate specific funds to it and plan out what percentage of the remaining funds would go into your accumulation of Bitcoin, backup funds and still leave some floating cash to serve as miscellaneous in case your expenses planning experiences a shortage.
You might get it wrong for the first month, however from the second month you'll start getting better at planning out your expenses and using funds judiciously to attend to it without being as wasteful as you can be when you don't plan for it and then you can keep getting better at both your cashflow management and may even consider increasing your level of aggressiveness in your periodic purchases.