You leave out whether you do commercial or residential.
I do both. My commercial pays me monthly. Instead of giving them to the 15th of the next month do what I do.
I give them two weeks from date of the last service. Example if the last time you did a property on 8/24 I invoice on the 24th and the payment is due 9/10. 5 days sooner then waiting to the 15th.
Try to get paid weekly on residential. Yes some people may not be home when you service them but why wait to bill them all at the end of the month. The more money you can have flowing in partial helps being caught in a bind.
Also make sure you have enough cash on hand to operate to cover lags in cash flow.