We're starting on our 5th year, running sessions mostly once every two weeks. The players have become very attached to their main characters buy now, so I'm much more willing to blast their machines out from under them then to take out a PC due to a random die roll. Though if they're dumb enough death is always waiting.
We're running a good ole mercenary campaign, with a twist. In universe, the player's unit started out on Canopus IV in 3011 with 2 salvage quality mechs, less than a half dozen vehicles and a short platoon of infantry. With smart choices (and not a little luck) they've grown into a short company with about 10 mechs in operational condition at anyone time, and a buccaneer dropship for mobility. At this point the campaign year is 3015 and the players are currently deciding how to profit from a civil war on Halla in the Outworld's wastes.
If they manage to get near battalion size I probably try to drag them into House battles on the DC/FedSun boarder.