hi guys 
first im sorry for my bad english hope you understand me :’(
I bought a slim ps4 in 2016 I’ve never used it is still in the box , my question the thermal paste in my ps4 slim can expire and degraded despite i never use it ? so next time if i want to play with it i need to change the thermal paste ?
Yes, the paste still goes bad over time. Plus the paste companies use is usually the cheapest they can get.