When should thermal paste be changed?

Hi,

I restored amps that are 35 years old and older, the white paste was all dried up.

Hello. If your temperatures are correct and it’s not ventilating excessively, there’s no reason to change the thermal paste, but you should ensure regular dust cleaning maintenance. Best regards

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Why place so much importance on the virtual world when nature is so beautiful and generous....................

OK, thanks for your answers.

It's true that I have no problems for now, the CPU runs at an average of 50° but it’s hot in my room; I took my PC to clean it at a friend's house with his compressor and there the temperature was around 30°, so nothing to worry about.
I’m just surprised that I don’t have to change the thermal paste regularly for maintenance.

However, I don't know the temperature for the VGA, I was using a program called Advanced SystemCare, which offered the possibility to see the main temperatures of the PC, but since the Windows 10 update, this program has a little bug. We can still select "show temperatures in Celsius," but the program doesn’t display anything.
It seems that the problem is the same on all PCs using Windows 10.

So I am currently looking for a program to do a complete check-up of my PC, a program that would also display the temperatures.

Here is the link https://forums.commentcamarche.net/forum/affich-32466344-check-up-pc#p32466520