At What Point is it a Business Expense?

[Barri F.]

I am moving out of my residence and will be renting it out.  The dishwasher died, and I'd like to be able to treat the replacement as a business expense and get the tax advantage.  I don't mind washing dishes by hand for a while, so at what point should I replace the dishwasher?  Do I need to wait until I physically move out?  Or can I do it once I advertise the unit for rent?  Or some other option?

Similarly, the unit needs some painting done and I'd like to know the best timing for that.