This is a good question.
Timber floors come in two basic types. Solid (fixed) and floating floors. The solid or fixed floors are the most expensive, but also far and away the most durable over time IF INSTALLED CORRECTLY.
They will either be installed direct to the sub floor (concrete?) and finished with an Acrylic or water based polish. The Acrylic is the stronger of the two, and a semi gloss will not reveal as much of the inevitable scratches.
Installation is critical due to the moisture content of the sub floor Vs the timber. The timber MUST be acclimatised for a recommended period of 2-4wks before installation. If the timber is to be glued it is even more critical that the moisture in the sub floor is measured and is below 5% as the glue provides a migration 'bridge' for the moisture.
Don't check it, and you will get the floor to warp at the first change of season back to that when it was laid. (you can always see the cupping in the planks by looking into the light reflections).
A floating floor is quicker and cheaper, yet a little noisier. It has a harder surface finish as it is UV cured, and products like the Fastwood come with both a wear warranty AND a structural warranty. All the noise issues are generally down to a non flat sub floor (it has a +/- 2mm tolerance per 1 meter) or insufficient expansion gaps (minimum 10-15mm EVERYWHERE) THe advanatge of Floating floors is that it can be installed in a day, doesn't need polishing and can be walked on immediately
Carpet comes in several styles of structure. The DHA usually uses a cheap loop pile called Polypropelene. This is a hard wearing commercial synthetic that is prone to flattening (therefore looks cheap within twelve months) and if not scoured (de-oiled) properly by the manufacturer, will stain easily and become soiled.
Wool is the best all round performer for carpets, and has both a natural stain resistance (not good for light colours) that serves it well for darker commercial styles.
NOTE: Carpet is often sold by the LINEAR meter, which is the width by 1 meter or 3.66 sqm. Beware the cost comparison.
Tiles come in two basic groups. Vitrified/ homogeneous/ porcelain etc (same material from top to bottom) and clay glazed (colour on top is different to the biscuit material in the body)
Floor tiles need to be a minimum of a Grade 4 (on a 1-5 scale) for long term durability, and the better the quality, the better the performance.
Vitrified will resist chipping, scratching, wearing and are easier to clean. They are also more expensive.
To answer the question, Timber is best for living areas, and carpet for the bedrooms.
The wear and tear on timber is the polish, not the timber. You just need to resand every 5-10 years.
The quality you choose will be dependent on the type of tenant you wish to attract (tenants are no different to you or I, they see S*#* quality just like anyone else), and the long term purpose of the IP. Just go into any commercial building and see what they are using (you won't see many cheap poly's)
Cheap quality is a false economy as you WILL replace it sooner, adding the labour on again each time. What you spend, IMHO, doesn't matter as both amounts are Tax Deductible. The finished effect however is markedly different.
Cheers
PS. Sorry it is such a long answer.