Some chambers have to be maintained more than others for sure. The majority of the people have the most maintenance after the warranty period. The cheaper chambers with mostly plastic instead of steel components and lower gauge thickness chambers usually are the ones that have the window leaks and zipper problems. Remember that this doesn't usually happen after about 2 years. I have not seen any chambers fail within the first year so.
Some of the compressors have better filters and some zippers need to be oiled more than others. Some hyperbaric chambers are harder to clean than others also. If the home is dusty you might have to clean the filters twice a month under the bathtub faucet rather than once a month.
The biggest maintenance concern for most is the fear that the zipper will get stuck while in the chamber if it is not oiled regularly. Some people over oil their zippers in fear that they will be stuck in their, mostly the claustrophobic people. It is called zipperophobia, the fear of having your zipper stuck at the worst possible time. I have a whole page on zipper concerns as it has recently become an issue among those that are cannot afford the oil less zipper chambers. See my zipper comparison page here.