Last year my CPA was able to write off all the purchase price of my new trailer. For my tax bracket, state, Fed, and local, that was over 30%. Spend $3k and don't pay $1k off in taxes. So in real money, after selling my used trailer and buying a new one, it was a good deal.
Actually, I bought 2 new trailers last year. The other was a 10K dump. Didn't spend enough money, had to send Uncle Sam a big check.