The link below is from Accounting Today, I subscribe to their newsletter, it's a good one, if you like tax news.
The AICPA just sent a letter to the IRS urging them to raise the safe harbor threshold for expenses from $500 to $2,500. There is an exception for companies with formal financial statements, so that pretty much excludes all small businesses that don't pay for formal accounting.
I notice that it was a frequent topic over at TA about when to expense and when to capitalize. It's a good article.
http://link.email.accountingtoday.com/52dec304c16bcfa46f0bf8b91wbor.19vt/VDgSFMPo9dijrDt8Ae1d3