How hard is really to install bathroom faucets ? scale 1-10

I would say maybe a 6. The only reason I rate it so hard is because you’ll be working inside the cabinet, on your back. It is usually difficult to access the threaded rings that hold the faucet down, you must seal the new faucet, and make sure you don’t have any leaks. If there are no shutoff valves you will also need to turn the water off before starting, and turn it back on after the repair.

If you have never ever installed one, expect it to be a 10. Your first one is always the hardest. After that, each successive faucet gets easier. Grab a friend and do it together and follow the instructions. You CAN do this, just be patient and do not try to rush the process.

Pat...honestly, there are more variations to know to give an answer. We took out an old faucet set and thought it would be a snap. It was a snap to install, but when we tried to plug the drain, the stem of the drain was angled and hit the wall so we couldn't close it. Other's might be fairly easy. The age of your sink and replacements available could vary by 1/4" and not work. If you're determined and have to get rid of the old, take it down with you to buy a new one. Measure everything for spacing and depth. Best of luck! I hope someone else has had better luck than we have.

Old plumbing is rarely easy, some little part will give you fits. It is a doable project, as everyone else said, you have to have patience.