I cycled with fish in my first ever tank (when I'd never even heard of fishless cycling) and haven't needed to realy cycle ever since then (just use old filter media from an established tank, or gravel/ornaments or run your new filter in an old tank for a while). However, if you are starting completely a-fresh, I urge you to do a fishless cycle. You may not be able to see the damage but it's there - just think of cycling with fish as if you were in a small pool for weeks on end swimming in your own waste. Ammonia causes serious burns and damages the gills. It also causes stress, weakening the immune system of your fish, making it more susceptible to disease. Shure, hardy danios and big cichlids do ok but try doing that with rams, discus or chocolate gouramies - and I see no reason why the common hardier species should get worse treatment than the fragile, sensitive fish just because they can survive it. It only takes a few weeks to fishless cycle, longer if you cycle with fish, and this time can be very useful for researching and deciding on the set-up. If more first-time fish-keepers, fishless cycled, I''m sure fewer would be attempting to keep bala sharks, clown loaches and common plecs in a 10 gallon. A little patience goes a long way with fish and I always say fish-keeping will not allow for corner-cutting or laziness so if you can fishless cycle, do.