I'm replacing an old laundry tray faucet where the pipes were sweated on. I have to decide to purchase a new fixture for sweat or compression fitting. I'm not experienced at this at all. Will the hired plumber have to replaced the length of pipe because it will be too short once cut? Also if he has to replace it does it matter whether it is a sweat or compression fixture?

If you hire a licensed plumber, let them make the call. Wheather it be sweat, compression etc, they should know the best way to do it for your situation. Please let us know what method they choose. Take care