I think with older laptops it is a good idea to "refresh" the thermal paste on the CPU and/or GPU. I recently picked up a pristine Early 2013 15-inch MBP for free and have been running benchmarks on it to see how efficient the cooling on this laptop is. So far I have not found any need to repaste my CPU/GPU as CPU temps have been running at a very consistent 102 degrees (under normal operations). Not bad for an 8 year old laptop.
I'm in the mindset of repasting older laptops as fresh thermal paste is never a bad thing as long as you know how to properly apply them.