We are in process of building a screened in patio (aka lanai in FL) and are going back and forth about having it sealed or not. The installer has suggested sealing. I should add our entire driveway is also all pavers like this. Sealing in and of itself requires regular maintenance and recurring resealing with the possibility of trapping the "salts" (efflorescence) that emit from the stones underneath it - creating a white hazy appearance. It also could mean paying to strip the sealing off if it's gone bad - or worst case replacing the pavers entirely.

On the positive side - sealing would provide a barrier against the mold and slime that accumulates on everything in contact with the 100% humidity cess pool that is Florida. Since pavers are porous, this kind of growth will be as happy as a pig in swill. It could be kept at bay with no sealing and regular pressure washing, and possibly chemicals. But sealing seems to make some sense in this environment especially.

This area will be just general use - almost never eating out (weather rarely permits that) - so more or less just an area for casual gathering and the dog to run and play. Point being - there's less chance of needing "protection" from spills - one of the big selling point of the sealing companies. There is no risk of weeds on the lanai part - there is a concrete pad underneath, but the driveway (on sand base) already has some, just 2 months old.

Of course the "sealing companies" tell you what they do is better than big box store DIY sealing because it's "special". It all seems like smoke and mirrors to us. We're just undecided though...