Before every trip I take a quick look under the sled, look at high fax, grab and spin the idler wheel and look for bad bearings or missing rubber, look for any bent parts in that area.
I then look under the front of the sled and at the bottom of each ski. Look for driping fluids from the belly ban area, damage to the belly pan and check wear bars on the skies.
Then it is a quick flip of the hood, check oil, hit the jack shaft and speedo grease zirks with a quick shot of fresh grease, while the belt guard is up for greasing, look over the drive belt and clutchs, check the chain drive adjuster nut to be sure the lock nut is in position, look at exhaust springs and grab the pipe to be sure it is all tight, quick overview for any visual damaged hoses or other items and I am ready to go!
This sounds like a lot but it only takes about 5 minutes and is well worth the time spent! The grease zirks under the sled I hit about once a month but the two noted above I grease the hell out of. Those bearings are common fail items do to lack of grease. Hope this is a help!