Certainly if the funds are there to do the whole house, then that would be the easiest on the family. You would move out once, remove your furnishings and then when you move back in, it is over and done with. Pricing does improve some when you move out and remove your things so that the work can be done. Some folks however prefer to see things develop and don't want to make that many decisions at one time.

There are several things to think of...are you prepared to move out....For the duration of a full house redo? Also are you able to make all the design and construction decisions in the pressured and rushed atmosphere of a project on a time schedule? If you have a plan, a good designer,an excellent contractor and no need to be involved in the details a full Reno could work...
An advance plan is necessary in any case but with a one step at a time process you have much more wiggle room for new ideas that pop up and changes...the down side is you have your home in some level of disarray for much longer...
So the big question is do you love the process or do you just want it done so you can move on with your life?

The cost issue is not a minor consideration. Living in a construction zone is no fun, either. Some rooms don't need a full remodel, probably just a paint job. However, if you have outdated electrical, plumbing and HVAC, or you face bringing the whole place up to code as soon as you open a wall, pick your projects carefully. Kitchens and bathrooms sell houses. Opening up walls for an open concept also is a wise investment. However, pouring so much money into a place that it is the costliest house on the block will pay you back much less than you might hope.

Thank you, we realize cost is not minor, which is why we are making sure we have the budget, plus 30% for overruns and an additional budget for moving out for 90-120 days plus living costs. Our house is only 10 years old, but there are major projects we want to take on, plus we have a very active lab and yes, do not want to live in a constant construction zone. I am not concerned about having to make quick decisions as the career I was in always required quick decision. We are not concerned with over improving as we have decided this is where we plan on staying for good. (If you saw our lot you would understand why).

Living through remodeling is not for the faint of heart. Doing the work in stages only prolongs the suffering. LOL It is imperative to have a fully developed scope of work before beginning so that your time out of the house is as short as possible. Select all items beforehand. Kitchen cabinets, tile, light fixtures , architectural millwork, carpeting, and even paint. It is the only way to finish efficiently and timely. Take the time up front to plan properly.
Once did an add-a-level with complete renovation of the first floor in 8 weeks. Took seven months of planning beforehand. All items were purchased and warehoused before the project started. Plumbing fixtures, tile, lighting fixtures, windows doors, etc. All purchased beforehand. Anything is possible.
A construction project is a partnership between you and your builder. You must be a complete team to be successful.
Other thoughts to consider:
I had a customer purchase a used mobile home and park it on the property and they lived in that for six months. We connected it to the house water supply and had the rent-a-John guy pump out the storage tank once a week along with the workers rented toilet. They sold it for what they paid.
Had another customer purchase another home and sold it at a profit when we were done with their renovations. Of course the real estate market is not what it was then. Cant beat living for "free"