Ask HN: How do you personally manage your cashflow?

I have several sporadic income streams that make it tricky to predict how much money is coming in each month. But I have pretty standard fixed expenses (rent, phone, internet, insurance) and some variable expenses (food, entertainment, gifts, etc).

I sometimes struggle to smooth out my inflows to match my outflows (and to make sure I have enough money in the right accounts so that everything works). Curious to hear about how this community manages their money. Do you use a specific app or tool? Or budget methodology that you've really got working for you?