How long should I wait for my PS3 to cool before playing again?

First of all, my PS3 is about 11 years old, I got it for Christmas 2009. It’s fan starts whirring really loud and the PS3 makes cracking sounds after 1-3 hours of gameplay, sometimes I’m lucky and it lasts for 3 hours, other times, not so much. When this happens, I quickly quit my games and turn off the PS3 and wait for maybe 20 minutes before playing again. Do you guys have better recommendations for how long to wait before starting to play again?