As JLC said, you have nicely finished doorways ... the only time you will see both floors is when you have a door open. And with the difference in lighting, you won't notice slight differences. Here's how I match or blend finishes: Bring home some samples of the prefinished you are thinking about and lay them in the hallway, parallel to the existing floors. Stand back 10 or so feet and pick the board or boards that you have the hardest time spotting. That's your match. Or, remove the boards that stand out ... what's left is the matching color. If you carefully pick the ONE board that is just inside the doorway to be as close a match to the older one in the hall it will make the blend almost invisible. Here, in an 1880s adobe ... the door stops where the pale wood is, and I picked new boards with the brownish tones of the old floor (upper part) to make the new flooring (running side to side) less conspicuous. (there was craptastical 1990s carpet and some wierd sill arrangement to deal with ... nothing in the house is square, plumb, or level). By matching size and rustic-ness in the new flooring we got a floor that blends with the old. Cleaning and refinishing the old floor (eventually) will make oit blend better.

Those are all good and valid points. To clarify any confusion, solid pre-finished hardwood floors can be refinished if you ever need them to be. Theres a bit more sanding involved to get the factory finish off, but it's done all the time. The floors get sanded down, and the bevels are no longer there, leaving you with a newly site-finished floor. The little grooved edges are called micro-bevels, and the durability of your flooring greatly depends on its installation. Those microlevels won't necessarily cause your flooring to be more susceptible to water damage than a site finished floor, as long as the installation is nice and tight. Yes, your hardwood floors will expand and contract, but every wood does this. It's just a natural characteristic. Quartersawn hardwood is known to have less movement than plain sawn, so if the gaps are a concern, you may want to think about looking into quarter sawn hardwood. Having hardwood in a kitchen is risky regardless if it's prefinished or site-finished. You just need to know, as a homeowner, that certain precautions need to be put into place to ensure the longevity of your floors. (Especially in a kitchen) Another thing I wanted to touch on was the fact that you said you had carpet in an area and tile in another. This would mean (hopefully) that the tile is sitting on either cement board on top of plywood, or there is a cement subfloor where the tile is located. This would have to be addressed when the tile is removed, and you are probably going to need some subfloor prep for your hardwood floors. Most likely additional plywood to bring the elevations of the floors to the same height. Many factory finishes are, in fact, more durable wear layers than a site-finished polyurethane coatings. And that is one of the reasons why many pet owners choose pre-finished floors. As long as you're not choosing a particularly soft wood, a prefinished floor would be just fine for your home. It would make sense, having children and a pet because of the time you'd have to vacate for the finishing process of site-finished floors. It would, overall, be an easier install. The quality and longevity of your hardwood floors depend on the quality of your subfloor, and the quality of the installation, not whether you have site-finished or pre-finished material. Good Luck! Pre-finished vs Site-Finished Hardwood floors

The acclimation you've been recommended to use is generally how we've done floors forever EXCEPT when using wider planks. As was noted above, have the plywood and wood checked. If they're too far apart the area can be dehumidified to bring the plywood moisture down and/or the wood will add moisture if it's particularly dry. Make sure the contractor is putting a vapor/moisture barrier (not retarder) between the concrete and the plywood. I don't recommend any barrier between the wood and plywood. Some pros have been burned using (probably cheap) water based finishes and refuse to use anything other than oil based. Others think you should use only the newest technology finishes and exclusively use water based. We use both. With a stained, hand-scraped White Oak, I would choose oil based polyurethane. No water based finish compares to the durability of oil modified. Considering the cost, it's a no-brainer unless you have special circumstances. As to staples vs. nails, we've used both and seen little difference in the performance. My preference would be for nails but the industry seems to have moved more toward staples.

Choosing the right flooring type isn't enough for your living condition. You will have to consider the types of cut: flat sawn, rift and quarter sawn, quarter sawn or live sawn. Quarter sawn and rift & quarter sawn will be best choices, because expansion and contraction is along the thickness of the wood. You will need climate control all year round. 70 degrees at 40 % relative humidity is where you want to be throughout the year. The use of a humidifier/dehumidifier will be needed year round. Although, engineered flooring is more stable than solid. Using the wrong wood specie in your living condition can run the risk of de-laminating with engineered wood. If, the top veneer is more or less stable than it's core and backing. You will experience de-laminating in extreme humidity swings. Take in account of what the engineered flooring is constructed of: mdf or plywood. The width of the flooring will account for how much expansion and contracting also. 2 1/4" strips are the most stable. As you go wider, expect to see more wider seasonal gaps. Proper acclimating is critical, should be performed with a moisture meter. For 2 1/4" strip flooring , sub-floor and flooring moisture should be within 4%. For all other widths 2% moisture differentiation is allowed or should not be exceeded. Don't forget proper expansion gaps, which is the thickness of your flooring, example: 3/4" thick = 3/4" gap. Sub-floor type and condition will affect the performance of wood floors. All this needs to be considered for the proper and successful performance of your wood floors.