Our address has been 411 Walnut (St. Brendan's in Green Cove Springs) for about 10 yrs. It is our legal address, so all our mail goes there. We periodically have it forwarded to our location.
We've rarely used General Delivery, preferring to have things sent to a marina via UPS. General Delivery requires a visit to the Post Office, usually a long way from the marina. We've learned that UPS is the most reliable, least costly, and most easily tracked way to get our mail. We get NO magazines or junk mail, and have the option to shred items before they're forwarded. Occasionally, time sensitive items are a problem, but with the way the scanning service works, we can view each item that's received (scan of the envelope) and if it's time critical, there is the option for the service to open and scan the contents. Great if we're on the move and don't plan to be at single location for any length of time. We generally know early enough where we'll be that we can plan for a mail drop to be there when we arrive. And, yes, we'll usually alert the marina, but we've learned that those who have a transient trade are very familiar with the drill, and it's rarely a problem.
That said, there have been times when timing went awry and we ended up extending a stay. It's part of the lifestyle, it happens. Our experience with St. Brendan's has been exceptional, they are great to work with. The service they provide is top notch, one aspect of our lifestyle that doesn't require a lot of effort. Highly recommend them.