As far as the buildup of waste, you should have the filtration to take care of the big particles of waste.
As far as the chemical levels, once established, the Nitrite and Amonia should be taken care of by the biological filter. One thing I'll be trying personally, is using a deep bed to develop the bacteria that feed off of the Nitrate instead of the oxygen. Assuming it works, it will cut down on my need for water changes by A LOT. So 2-3 months should be feasible.
The only downside to not doing water changes, is that if you have a saltwater tank, you will deplete the natural vitamins and trace elements that are normally in the water (they have supplements you can add for this). As far as freshwater water changes, you'd have to be insanely lazy to not do them.
They have a pump you can use to hook up to the faucet to drain the water from the tank directly into the sink, and refil the tank at the same time. Add some water conditioner once done (or RO water if you prefer), and you're done... 15 minutes for your average tank tops. And this little gadget is CHEAP....$15 at wal-mart.