sitting for a couple months or a couple years should not really impact your gear too drastically unless you didn’t take good care of it on the last dive and put it away dirty, salty, or all scrunched up in the bottom of a bag where it sat getting moldy. I’ve used regs that hung in my garage through 2 or 3 hot summers and sub-zero winters and they work fine. I also once had a BC that I didn’t rinse properly after being in the ocean and the valves were all seized up after a couple weeks.