Obviously the rules vary and there are some rules that are not well known and can bite you. For example, Tim R has a boat registered somewhere other than NJ where he lives. If the boat ever shows up in NJ waters wjile he still lives here, the sales/use tax is immediately due to NJ.
If you have a boat registered outside of FL but want to keep the boat there for more than a short time (30 days??), you register in FL with your homestate numbers and put a FL sticker on the boat along with your out of state sticker.
I think both requirements are more often ignored than not. Times are changing, however, and the failure to comply, when caught, adds not only to the tax revenue stream but also the penalty and interest revenue stream which in NJ can be substantial.