I have seen so many Playstation's being burnt out in under half their specified lifetime. The most common problem is the lasers being burnt out. Here a few tricks to help give your PS2 a longer life.

NORMAL PS2

1. Firstly, if you leave your PS2 running overnight or for long periods of time, then you will burn out the motor in the unit and after a while, you unit will not perform very well. To prevent this, simply turn off the unit by either holding the green button down for 2 seconds (the green light will change to red) or by using the switch at the back.
   
2. It is even worse if you leave your PS2 running with a game in it. This not only wears out the motor but it also burns out the laser. Your laser starts of with a life of 4 years, then if you put a mod-chip in (something that allows you to play burnt games) then the life of your laser is halved to 2 years. Then if you leave your PS2 on with a game in it, you can imagine the stress it will put on the laser. Eventually, you will have to pay over $100 for a new laser.

SLIMLINE PS2

1. Steps 1 and 2 are the same as the normal PS2, expect on the slimeline unit there is no switch at the back , there is just a button at the front to push.
   
2. Steps 1 and 2 are the same as the normal PS2
   
3. There is just one thing you shouldn't do with a slimline PS2. That is to open the CD cover without turning off the unit. This just wears out the laser even more. Simply make sure the unit is off before you open the CD cover.

I hope this helps and enjoy your PS2!