No battery, but most electronics do have electrolytic capacitors, which normally have liquid chemistry inside. They have a life expectancy of 10-15 years, except for the bad batches from the 2000's that died after 1-4 years.

Heat is the enemy of electronics. Things DO degrade when kept hot for extended periods. Keeping things cool is worthwhile from a longevity point of view. I arrange most of my networking gear for optimal convection cooling, which usually means "mounted sideways on the wall".

Cheers