A little more info would help, not all lasers are the same. A 532nm green or any other DPSS laser is more fragile and will break easily and is temperature sensitive, not so with direct diode lasers. I keep a rubber lens cap on my lasers so the lens doesn't get dirty, often when you get a lens dirty it will be ruined and not cleanable. If you do clean a lens, only use alcohol, if it's an acrylic lens just through it away and b2dc1e2341duy a new one. If the laser won't be used for many weeks or months at a time it's not a bad idea to remove the batteries. At first I left my lasers on a table and in a cardboard box but I eventualy had enough lasers I decided I needed a case to keep them in so I got one of these:
http://laserpointerforums.com/f52/pelican-storm-case-im2200-pic-heavy-90406.html
Alan