Sanding wood floors yourself will definitely save money, and even an inexperienced homeowner can likely do a better job than the lowest bidding handyperson who quotes on it. Once you understand the basics, a quality final product is more about patience than anything else.
Ultimately though, once any ridges between boards are removed and you won't trip, it's all about aesthetics. Upon completion your floor will be a work of art to show off, then your kids or your dog will come in and it will just be a floor.
Floor sanding machines:
Buffer sanders work in a circular motion, it is the same machine that is often used to polish and clean industrial and commercial floors. If you've used one in any other application you could give it a try, but sanding
floors might not be the best place to learn. They have a very sensitive balance and will take off across the floor if you don't yet have the magic touch.
You will need to buy several different grits of paper and some cushioning pads. These are available at the rental counter, someone there can likely help you determine how many of each you will need based on the square footage of your job, but buy a few extra. This is a common practice, and you will be going back to return the machine anyway so there is no inconvenience or wasted trip.
The pad acts essentially as a shock absorber, giving the sander a smooth ride and ensuring even removal of material. After a while (a couple of hours or so) the pad will become compressed and need to be replaced.
Installing paper and pads is quite easy. The paper sticks to the pad, you then just drop it on the floor (yes that's right, paper side down) then sit the sander on the pad which will stay simply due to friction and the weight of the machine.
Old pads can be cut up and re-purposed into excellent floor scrubbers.
Square vibrating sanders are the easiest to use and the hardest to screw up with. You can rent one at most major home building stores, and like with buffers, you'll need to purchase pads and paper. This is really you're best option if you haven't sanded floors before.
Both buffers and square sanders will come quite close to the walls, but you'll also need a small orbital hand sander to do around the edges. For new floors, keep in mind your baseboards will likely cover a good 1/2 to 3/4 inches away from the wall.
For using a buffer or square sander, the process is the same. You start with a really rough paper that will smooth out any ridges between boards and give you a uniform surface. From there each different grit of paper is designed to remove the ridges from the paper before.
Papers will go in sequence starting at 36 or 40, then to 60 grit, 80 grit, 100 grit, and 120 grit. You can go up to 180 or 220, but before you do that, I'd think about hand sanding 2 sample pieces and putting some oil on. If you can really tell the difference between a 120 and 180 then go for it. I'd do it for a paying client simply because there will be an initial nose to the floor inspection, but for my own floors I stop at 120.
This is where things get a little different, and the stakes go up. If sanding a floor for the first time was like learning to drive, choosing a drum sander would be like choosing a stick shift instead of an automatic.
Drum sanders have a rotating belt, and do a quick and relatively clean job. But they can be quite
tricky to learn, and have a lot more potential for causing damage if you do it wrong. If this is the machine you choose, make sure you start out in a place that won't be highly visible.
There are two types of drum sanders; tip sanders and lever sanders, both of which operate with sandpaper belts. Of the two you are most likely to encounter a tip sander, as they are the easier of the two to learn and use. They have two wheels that you tilt the machine back onto to change directions, whereas a level sander mechanically lifts and lowers the drum.
It's important to start the machine with the paper OFF the floor. Once you tilt it down and the sandpaper touches the wood, it will instantly start pulling you.This forces the operator to switch actions from pushing to pulling.
For all types of sanders (especially drum sanders), it's important to keep the machine moving. If you stick around in one spot you will start to dig yourself a bit of a hole that will be hard to fix with the next grit.
After ever stage, do a quick look around to see that you've got all the scratches from the pass before. Once you've done a 120 grit pass, for a really smooth surface you can wet it (that brings up all the fibers) then wait for it to dry and do a quick pass with a 120 screen.
Skipping a step might seem like a time and material saver, but it isn't. If you go from 60 to 100 grit and don't do 80, you will spent a long time trying to wear down ridges with a paper that is just too fine for the job.
Really the only step you can feasibly skip is the initial paper you choose. If the newly installed floor is quite uniform, you may be able to start right at 60. How long you spend on a floor is really determined by how well it is installed and how long it takes on your first pass to get it to a point where you are happy.
The one thing that can really expose cut corners, will be if you choose to stain the floor. Floor stain will make any scratches and flaws a lot more visible.
Be sure to wear proper protection from breathing dust particles, especially if you are repairing old floors with a finish on them. Small paper masks protect you a little, but not much. A respirator is a good idea.
Be ready with a broom and dust pan, and ideally a shop vac. Be sure to use vacuum attachements with soft bristles, hard plasic will leave lines across the floor. Also, if you vacuum with the gain, there is less chance of leaving any visible marks.