$1800 - $400 = $1200
$1200/4 = $300 PER DOOR

#300 per door is too high for a modern house, but if he has to drill the hole, set the hinges and compensate for 90 years of settling and warping when he gets the door to fit, it's not exorbitant. That takes practice and skill.

What are the other estimates? And has this person worked on houses of similar vintage? Have you checked his references?

My method is to get at least 5, throw out the highest (cause he's overpriced) and the lowest (cause he's going to go broke before he finishes), and pick one of the ones in the middle with the best references for the work I'm planning.

I had salvaged doors hung by a trusted carpenter. He and his partner were here almost all day hanging two doors. Both had to be hung multiple times as they'd attempt, plane, adjust, adjust hinges, etc. It was fiddly work putting old doors from another house into my old house.

Prehung doors might take less time to install, so $300 per door might be steep. Ask him/her how many hours they expect each door to take to install. This might get their insights on how they expect the job to go. Perhaps they are concerned about fiddling with all the trim and getting it to look right.

But it's always good to get other estimates, even though I typically don't. Do as I say, not as I do. I have long-standing relationships with my carpenter, plumber, and electrician. They come, do the work, and give me a bill, and it's always reasonable, usually less than I expect, and less than their official hourly rates. But I suppose my situation is the exception to the norm. Until you have a relationship like that, multiple estimates are the way to go, and I suppose even afterwards, it should still be done.

Thanks for the feedback, we also thought it was a little high. We are actually in the middle of a kitchen remodel and these doors are off the kitchen area so we decided to update them as well....the estimate came from the contractor who is doing the current work, so it would be added on as part of the job. The house is 82 years old, so I imagine there will be some "fiddling" to get the fit and trim right.

"...these doors are off the kitchen area so we decided to update them as well..."

What is wrong with the old doors?
If they are original no new doors are going to be as well made in material or construction.

I grab those old doors all the time.
Clean them up and they are better than anything you can purchase now.

I agree with Brickeyee. Old doors are much better & it shouldn't cost nearly as much as the new pre-hungs. I've had doors moved to different rooms on several occasions & each time it took a good carpenter about 1/2 day to remortise the hinges, square the door & get it hung; neither time was the frame terribly out of square so I may have been luckier than most. It's all about someone who knows how to hang an old door as opposed to a pre-hung - I think it's fast becoming a lost art.

Prehung doors are MUCH easier to install than old doors as long as the area is torn up already. If all the trim has been removed, it is just a matter of sliding them in and shimming. The "prehung" part means they are already level and square in their own opening. The opening and the walls don't need to be perfect. The thing that can trip you up is if the floors are quite unlevel.

If the current door areas are not torn apart already, then it can be time consuming. They will have to remove trim on each side and then reinstall it once the doors are up.

Also, before you buy, you need to check the depth of the door jam. Most of the prehung doors are sized perfectly to slip into modern construction - ie 2x4 + drywall. If you house has original 2x4's (really 2x4, not the modern nominal label) + lathe + plaster, your walls could be considerably thicker.

I paid $50/hour for door hanging, which amounted to between $50 and $200 per door, and these were slabs that had to be laboriously fitted into old jambs. I'd say $300 each for pre-hung is pretty steep - but there may be regional differences.