Ah, washers and dryers.... If you live an in area where providing them can go either way, here is a simple script that can save you lots of time and money:
(speaking to the new tenant) The previous tenant left the washer and dryer. We are happy to pull them out of the unit if you would like. If you would rather, we can leave them for you to use. We would just expect you to to fix anything if they break....
No one ever asks that the machines are pulled (your local millage may vary)
A couple of notes:
1) Make sure the machines are in good working order to start
2) Explain that you'll fix any leaks (you don't want them sitting on a leak problem)
3) Sometimes the machine will come back to you at turnover broken. Ask a month or so out so you know the situation
4) Tell the truth. Our units did come with washers and dryers to start. If yours didn't, modify the script to fit your scenario, "If you want we can provide washers and dryers as a convenience, we would just expect you to to fix anything if they break....