First of all I am not an accountant and I always defer to mine in these matters each year. So take anything I say as my own experiences and not rule or law.
Traditionally in buying small stuff I always section 179 everything. When it comes to larger things, stuff over $1000, in the past I have done depreciation schedules. However in the last couple of years my accountant has 179 more stuff because the limit is like $100,000. In my case the "more than 50% business use" has always applied. Not everyone fits that though and there is where the accountant can be most useful.
Her thoughts on this usually include questions about the long term use of these things. Namely are there any future changes in potential business use? Reduced business use can be complicated and require me to give some of that deduction back in the future. Also weather I'll need to save some of the deduction power of these items on future income. In other words if I buy a bunch of stuff now with some "extra cash" I've got that I won't see coming in in future years than I should 179 to the limit. If however I anticipate higher incomes in future years then it might be better to reserve some of that depreciation deduction for that income.
So last year I depreciated stuff that I have loans out on but 179 stuff I paid cash for. This year I may depreciate some stuff to hold back some deduction for later.
I always defer to my accountant who has a better perspective of my current and long term financial health than I do.
These links, if still up to date, may be useful
http://www.turbotax.com/articles/Wat...Deduction.html http://www.bankrate.com/brm/itax/Edi..._deduction.asp http://www.turbotax.com/articles/Whe...epreciate.html
So lastly, just like we say about teachers, if you don't have one, get an accountant.