Time charges things! In years past the TIM paste was still based on old formulations which tended to break down. Todays TIM is much better! I doubt you’ll need to refresh it to gain enough performance improvement for the amount of work and risk if you’ve not done it a few times before.
I would focus in keeping the fans and heatsink fins clean of dust and debris, as well as dusting off the logic board as well if it’s coated up. I also recommend installing a good thermal monitoring app so you can watch things over time. I find [https://www.tunabellysoftware.com/tgpro/|TG Pro] is one of the best and it allows you to export the data to a spreadsheet so you can track over days, months or years how your system is doing thermally.