won't wake up after too many sleeps?

From 2005 to recently I used a Powerbook G4 (it still works); recently have bought a MacBook Air. With the Powerbook my habit was to rarely turn the computer off; I just put it to sleep. In the last year that I used it, the computer would sometimes go to sleep, sometimes literally between keystrokes, and I would be unable to wake it, had to pull the battery, unplug the power cord, and then hit the power button to turn it off, then could turn it back on again. Occasionally it would go to sleep while it was powering up. The problem most often occurred when I was using the computer at close to its limits with respect to ambient air temperature, that is, it was in the 90s or 50s F. Is there any connection between continually using sleep mode instead of turning the computer off and problems with sleep?