There are two types of enclosures
Perimeter - leaves jumper vulnerable to the springs.
Interior suspended - keeps jumper out of springs.
Weather covers are intended to keep debris, chemical laden moisture/dew, UV/sun
off the basic trampoline. They are supposed to breathe and not collect
moisture. When you remove the cover debris goes to the ground.
Removal and installation is fairly simple and straight forward.
Any one that has an enclosure has a debris trap (leaves, pine cones, trash,
etc).
Any weather cover will just provide another layer to the trap.
Installing and removing a cover (normally through an access point in the net
that is 3 feet above the ground) is cumbersome but does not do anything for the
debris. If you pull out the cover to jump - where does the debris go? It
comes out possibly with the cover if you treat it like a table cloth (fold into
middle and pull it out the access point). You then shake the cover and get ready
to put it back inside the enclosure after jumping ceases. We do not
envision many owners or their children doing this.
Based on this - we see no real benefit for the use of weather covers when enclosures
are installed on the trampoline unless the owner
wants to spend a lot of time installing and removing the weather cover.
The only reasonable solution is to place the trampoline and enclosure in an area that has a minimum amount of debris falling into the enclosure.
A cover is a real "life extender" (mat, frame pad) for trampolines without an enclosure.