A bad connection to the points on the tube won't hurt the tube itself directly, but as it's passing very high voltages it's a bad thing to have either contamination, corrosion or a weak connection which can lead to arcing. If it is arcing, it will burn through the wire and/or post on the tube. In very rare circumstances it could crack the tube. Obviously, there are other issues if the wire should come disconnected.
Overall, it wasn't difficult to replace the tube. You just need to work slowly and watch that you don't do something that can break the new tube. The part that made me wince was putting the little bits of hose onto the bits at either end of the tube. Saliva worked really well. I had one set of hose barbs that were only a little wider apart than the thickness of the hose, and were not in line with each other. It was tricky, but managed to massage the hose into place without any kinks.
Current Equipment: FSE 45w Deluxe CO2 Laser 5th Gen w/ Rotary
South San Francisco Bay Area - Sales and Support Representative for Full Spectrum Engineering
White Light Laser, Morgan Hill, CA - - 408-47-LASER - - Skype: whitelightlaser-thomas