Can't speak for the States, of course, but I take exception to the throwaway that the self-employed cheat more than other people.
For a start, nobody paid me cash. Everything was invoiced and paid by cheque that was paid into the business account. I can't speak for those working for the general public, but I sure wouldn't trust a cheque from one of them! In the brief period where I let the great British public cross my humble threshold, I was on a rapid learning curve about just how uncommon is common decency. From clients who vanished with proofs, to those who simply never showed up to collect, it was an unmitigated disaster. Had I not had my Damascene moment described some time ago, I would just have shut the studio door and handed back the keys.
Apart from that, I took advice and used an accountant from year 1, the advice being that it was the one way to keep a friendly relationship with the taxman. Expensive, but also saved me a lot of grief and even more painful learning curves which, clearly, did not begin with digital photography.
Rob