aside from the lemons, a working omen is easy to maintain. i just wipe down the body and oil the hammer after everygame. i also add a few drops in the asa so a little bit of oil can lubricate the hard to reach places. just wipe the bolt after you shoot it w/o paint to make sure theres no oil on the bolt. thats pretty much it.
I've only had to change my bumper twice, and i've played with this marker every weekend since late july. If you adjust your recock correctly they won't get destroyed so easily. Also it will still work if its beaten up and torn up. It's job is to take punishment, so you don't change it even its begging for mercy... I only changed it when it was completely torn in two. My omen still worked great.