Pests and animals problems

Mice keep getting in through holes and gaps in the walls

Patching the holes you can see does not keep mice out, because mice get in somewhere else and chew new ones. Seal the entry points with copper or steel mesh set in sealant, then patch the cosmetic damage afterwards. A mouse fits through a gap about the width of a pencil, so the gaps that matter are the ones around pipes, wires and the bottom of the wall, not the chewed drywall in the middle of a room. Do the sealing first and the patching last, or you pay for the patch twice.