How long is "average use?"

[Geoduck]

I've been using my PS2 for about a year now, and the machine starts to show subtle signs of wear and tear (eg. I can now hear a whirring sound whenever the disc drive reads the discs--even on DVD's, not just CD's--like when you run a CD on a PC's CDROM drive.)

Right now I'd like to try to keep from using the PS2 more than I should.

This is how I've been using the PS2 for the past year:

Daily basis= 2-3 hrs (working days), 2-5 hrs (on vacation, or when friends aren't available for a few drinks at the pub)

Usage=PS2 DVD-R format games only (I retained my PSX for PSX games)

DVD playing= none

Environment= Air-conditioned (always), machine is kept under a cloth when not in use, to keep dust out

In short, is this "average use" or am I using it more than I should? Sorry if I sound psychotic in my maintenance, but my PS2 has been accidentally tripped on before (who'd do it on purpose? ) and I don't want to shorten its lifespan anymore by overusing it.

A thousand apologies for asking a less-than-technical question, and thanks in advance for any advice!