I just bought this hard drive and I'm using it as a secondary backup disk in my computer, the temperatures ranges from 38-45 degrees Celsius.( This hard drive is latest fastest 1tb from WD 7200rpm 32mb cache)
What should be the optimal good temperature for a hard drive so it can last longer?
Are you serious? So long as it's not on fire, it's going to be fine. You're just using it as a backup on a computer. Not a server. Not some huge important set of data, like some financial or hospital database. By the time this backup of yours is even remotely in danger, it will have failed for other reasons, or it may be so far forward that the great apes and cats will have gone extinct, yet your drive lives on with old copies of tv shows you're backing up.