The things I've seen written off by numerous tradesman of various different practices...that was fully ok'd by their CPA's...would make alot of folks on this threads heads spin.
There are so many things that can be used personally and for business purposes that may or may not be used only for business purposes...not sure where the burden of proof lies...but none of these guys I know have been audited in decades of doing so. Some are more cautious than others.
My brother is not one of those, how he's never been audited I have no idea. He doesn'tmake a pile of money, butbhe doesnt pay

in taxes either. I dont know how they choose to who to audit, but I can't help but think you have to put a pretty big target on your back and really push the limits...or maybe all these guys are just lucky?
To quote the advice I was given by a CPA who " colored outside the lines but still on the page"...
"If you want to lie to dodge taxes, lie about your deductions, not your income. If you get caught you'll pay what you should have and a bit more, but if you lie about your income your probably going to prison"
Alot of people see "write off" and think people are getting stuff for free...your still paying for it, just at a discount of whatever your tax rate is essentially. For most thats 30-40%
If thats worth the risk to you or your on the "it's only illegal if you get caught" or "taxes are theft" team...then expense away i guess.
All comes down to your risk tolerance I suppose.