I need a script to attach to NPCs who are equiped with armor and weaponry that will remove their current equipment and replace it with the same stuff on a set time or after a time period. I had a script but sometimes it doesn't work; sometimes the NPCs have double the equipment in the inventory, sometimes they are left with damaged gear that doesn't get replaced.

One thing I have seen with mods that do this is to replace the entire NPC with another one that has the equipment on them that you want. So, the display name and look is the same, but the NPC formid is different for each gear set up. So, you disable the first NPC, then enable the new one. This could even handle any differences in dialog based on the different equipment, or you could just clone the entire dialog tree. This can also allow a change to the NPC skills and levels for the new gear, if you wanted that.

I am sure there is a way to script the new gear to the NPCs, but that might get unmanageable for more than one or two NPCs due to some of the issues you are running into now.