I would appreciate any input regarding preventive maintenance I or my client call do for their Nortel ICS and Call Pilot Mini.

1st & most important, sell them a quality UPS Battery Backup system to be installed B/4 both units.

Make regular backups of the CP.

Avoid having non-trained personel trying to do any programming on either system.

If you're talking about the phones themselves, avoid eating & drinking near them.

well if you are from canada also avoid letting bell touch the system, i went to a customer site after bell came to add a line, they went and made some programming changes on the system that had to be un done!

Where you are is not relavent, but Jay makes a very valid point. If at all posible have just one company, preferably one tech working on it to avoid those types of problems.

I personally carry a programming record for each client in the truck. If someone calls I can do a quick check to see if they can do what they want &/or give them a ballpark quote on the fly.

exactly, im lucky 3 of the systems i maintain are for my primary employer, but it is maddening when you arrive on site and the phone company, contracted to install a line or 2 to a bix and they proceed to hook it to the system and add set relocation to the system, this is not what was asked