We did our whole house (not in one go but one room at a time)
Depending on room size, the average room will take most of a day. Go over it twice (once lengthways and once crossways) with heavy duty sand paper, then repeat with finer sandpaper.
Don't forget to get an edge sander for the edges.
Be prepared for lots of noise and lots of sawdust. But it is easy and therapeutic. NO need to get a man in really. Honestly. The worst bit is the dust everywhere and you will still get that if you get a man in!
Make sure you pull all protruding nails/screws out of your floorboards.
If a wood stripped floor is waht you want than do not cut corners and put down carpet. We did that 3 times, and each time regretted it. Carpet just did not give us the look we wanted and it was so hard to keep clean. Also, you will need to have carpet cleaned / replaced every few years (well we did )
Once you have gone through the pain barrier of doing your floors it will be done forever!
I am a crap DIY-er but am okay with floor sanders. (even the first time I used it, after it ran away with me and crashed into the skirting board)
And dh enjoys it as it is another toy to play with!
Go for it and when it is all done (and dusted!) you can stand back and say 'we did that!'