We just went though a major remodel. What a stressful and expensive PITA. Everything said above was spot on including it taking MUCH longer (estimated six weeks, ended up being ~16) and, once walls/ceilings were open and issues were found, we needed to make changes/fixes that added to the cost. Did I mention it was really stressful?
Here's a few thoughts:
- Work with an Architect and get a detailed design. And, REALLY think about the design as you'll be using that design to get bids. By getting the details nailed down, you can avoid change-orders (things you decide to change things after work starts can really mess up a budget and timeline).
- While a GC will add to the cost, the subcontractors he uses know he'll have more work for them on the next project so (theoretically) they'll do a better job as he'll hold them accountable.
- Make sure the GC/contractor statement of work/contract is very specific (like number of outlets, flooring allowance, paint colors, baseboard allowance, windows, who pays for what materials...) on what will be done and the cost. No verbal agreements, get it in writing.
- If a change-order is needed, get the details and cost in writing BEFORE work on that change starts.
- You'll likely have a payment plan ("x" owed at start or completion of "y" part of the project). Make sure the last payment is due after work is completed and, that the final amount is big enough that the GC/contractor is willing to finish the job to your satisfaction.
- Interview several GC's and pick one that has both good reviews AND seems to be someone you can get along with. You'll probably have some tough spots and, it'll be better if you start off liking the guy.
If I were you, I'd hire an architect, get a design done and get a couple of GC bids for the work. Then you'd be able to make an informed decision on how much you need to save (count on a cost of at least 20% more than the bid as issues are almost always found on old houses) or if it makes sense to sell and move (hopefully to a house that has what you want and that someone else has already renovated) or, live with what you have.
Good luck!
PS: One thing that comes up often: once part of the house has been renovated (or an addition is added), the rest of the house may look a bit shabby in comparison. Beware of the potential domino effect of renovations!!!