The way I see it, you should wait until the end of the month and build up as much as you can. Then you get paid around the 20th. If you cash out like on the 15th, then any offers you do after that, you won't get paid for until the 20th two months later.
Example: You have $25 and cash out on the 15th of September. Then you do another $10 in offers before the end of the month. Around October 20th you get paid your $25. In October you complete another $15 in offers and cash out on October 30th. You will get paid $25 around November 20th.
Instead, you could have waited until September 30th to cash out and received $35 around October 20th.
Is it a big difference? Depends on how badly you need the money. There is a time value to money. That is why you pay interest when you borrow. The sooner you have it in your hands and working for you the better. Probably does not matter much when you are talking about the dollar amount that I am making here, but if it were a large dollar amount, it can make a big difference.
Sorry, probably put you to sleep with that explanation, but I worked in finance and am kind of into that type of stuff. Too bad I have never had any money to apply my knowledge to, but I keep trying!