That all depends on who is doing the sanding and how the floor was worked in the past and how it is worked in the future. If the goal is to remove as much damage as possible (i.e. scratches, stains, poor past sandings) then you will reduce the total number of sandings that the floor will endure before you work the life out of it. My experience is that most solid hardwood can easily take at least six complete sandings in its life. And you can expect a few more if you can accept less than perfect results. A floor that has been expertly resurfaced and then finished with the best products available need not be resanded often. In fact, such a floor that is well maintained simply needs to be recoated ten or fifteen years later to restore the original appearance and serviceability. Hence, a hardwood floor can last 100 years or more...that should be enough...yes?

Don't forget that it also depends on the type of wood you have...some take stain better than others...I have red oak... I decided to do English Chestnut. In theory I love a dark floor but I worried about dust and maintenance and scratches showing. Another BIG factor was that I always do very dark funiture...so I wanted some contrast....The color did come out a little lighter than I thought, but I definitely don't think it's red bc I hate reddish floors...I'd say it's a nice medium, neutral tone...the dark tones really work well with the dark furniture. Here are some pix: This is when we first moved in...with our temporary old loveseat and rug, etc..it looks pathetic LOL..but it shows the floor with natural light which is how it usually looks...oh, it's a satin finish top coat

Your kempas has much the same coloration as your fir, which I bet is long leaf heart pine and not fir. How are your stairs constructed and from what wood? Wood usually looks good with other wood, unless it is colored to look unnatural. What wood you choose and what color you go for is your decorating decision. Good luck.

Do NOTHING until that heating has been up and running for about 2 weeks. Moisture readings WILL BE TAKEN before (right now), during (the day they start sanding) and after (the day you walk through to see the final coat) the sand/refinish has been completed. This is non-negotiable for your installer. Because you chose the installer, you are HIS/HER GC. The real GC is responsible for everything s/he hired for your project. Look to your contract to see if there are penalties you can *refer to (small threat...not a big one) to encourage work to be completed by 'such and such' a date. Do NOT let the project move along until the heating is turned on. And be VERY careful with in-floor radiant heat under the wood. The in-floor radiant can ONLY be increased very, very, very slowly. It should take 3-5 DAYS before the in-floor radiant will be in the range of 'living conditions'. As soon as you allow (ahem...you are the flooring GC...you are responsible for allowing your subcontractor back onto that floor) the flooring contractor access to a floor that is improperly acclimated (regardless of when it was installed it is now officially 'unnaclimated' because of the lack of heat') then you officially take responsibility for a floor that has issues. Pause the project, bring up the contract with the real GC, point out the penalties of halting the job (he will incur) and the halting of payments you will be forced to engage should the electrical be delayed any further. Hardball sucks but sometimes it comes down homeowner putting their foot down. Sadly you have to do this TWICE. First with the GC and secondly with YOUR flooring contractor.