I never pay the winter bill until I get an invoice after the boat has been hauled out and the service is complete. Even then, I don't often pay in full. I'll pay in full by spring before the boat is launched (because the winter storage includes spring launch) but I have never been pressured. Sometimes, when I leave an unpaid balance a bit too long, I'll get a hand written note on the bill from the office that says "Please pay in full" with a smiley face. We must be quite a bit more relaxed in south Jersey. They like my yard bills, for sure, they have collected some pretty hefty sums over the past several years. I'm guessing they know whom to trust. The out-of-ordinary stuff, I pay when billed, so they seem to know my habits.
I'm equally lax on the summer fee. I usually get a deposit in when asked (which is typically late fall) but I often don't pay in full until the launch and I have even held out longer, as if I'm paying by the month (they do have a monthly fee if you aren't spending a full season at the marina, or at least they did). The marina has been almost exclusively sailboats, which means it has been half filled for the past 6 years as far as I know. They don't seem to mind when we move our boats to a safer location when weather is coming in. Last year, I moved in to a more expensive slip (larger size) when we had a hurricane move thru in early August. I liked the spot so I stayed there for the rest of the season. They didn't demand any extra money. In fact, I didn't even know that it was a more expensive slip. I wanted it this year and it was a surprise that it had already been delegated to somebody new (they had me down for the old slip). I was a little lucky to get a new location that I wanted for the same price as last year. They are filling the marina with more sailboats and quite a few more power boats this year. The marina is more filled than I have ever seen (but not anywhere near the heyday in the 70's & 80's or even a bit later).