We have had very minimal problems with our 2007 3075RL.
Front and rear decals cracked and peeled after about 6 yrs. But Keystone was still supplying new ones free then and I replaced them myself. Sides still look good.
Checked all caulking on roof and recaulked where needed.
Attic vent caps were looking chalky and brittle a couple years ago, so I replaced those. Bought two new ones, but bases were still good so I just unscrewed the caps off the new ones and screwed them onto the old bases.
Plastic dryer outside vent same condition as attic vents. So replaced it.
Black tank vacuum breaker valve leaked, so I eliminated it.
No name DVD/sound system died years ago and I replaced it.
Replaced old boat anchor TVs with new larger Samsung LED TVs.
Did same repair as noted in this discussion.
http://www.montanaowners.com/forums/...ad.php?t=75667
Otherwise, just routine maintenance, tires, bearings, battery, water heater anode rod, etc.