Consider the set of all companies in the economy which spent $15k last year on "computer hardware." How many IRS hours would be required to read all their returns, given that they are sitting in a pile. How many would, on examination, show a deficiency? How much would those deficiencies be worth, on average? What's your ballpark estimate for how long it takes a government employee to put through a single routine non-trivial work order?
Suppose the IRS sits down with a randomly selected small business for a site visit audit. Suppose they budget 2 hours onsite and 8 hours offsite for the audit. How many of those minutes do you think they will spend on that line item, specifically? Does it allow them to do more than ask "I see your return shows $15k on computer hardware. What was the hardware? Can you show me your records?"
https://www.treasury.gov/tigta/auditreports/2015reports/2015...
It doesn't (and can't) divine "Did the expense on this business return factually happen? Was it for the operation of the business? Is it standard and ordinary?"
That said, I’m always vaguely terrified each year when I deduct the low five figures I’ve spent on bare meral server hardware. Being audited remains in my top ten fears, even though I don’t try to evade taxes. I always wonder if someone at the IRS is going to see my return and say, “He paid this much for ‘Computer Hardware’? That seems fishy.”