Hi All
I agree with everything written above.
Except in certain cases, stain is always applied to bare wood as it needs to be able to soak in; any coatings already applied will prevent this. Staining wood has at most a minimal affect on sealing the wood.
Some waxes (ours included) can be applied to sealed or unsealed wood (regardless of whether a stain has been used) and give good results. Others (the ones really intended for polishing furniture - it should say on the label) should only be applied over a sealer. This is because they are slower drying and the wax can soak into the timber leaving nothing on the surface to buff.
Sealing the wood can be done with either a Sanding Sealer, a Lacquer, an Oil, a varnish etc then followed by a coat of wax.
Using a sealer (any of the above) will make the coat of wax more resilient and will require less wax to be used. As the wax is likely to be, relatively speaking, the softest finish it is an advantage to use as little as possible (hang on... I sell waxes... did I really just write that???) as there will be less to get damaged.
It is possible to build waxes up to a very high gloss by applying several coats, but it would be very prone to marking when touched.
Finally, yes, wax is very easy to repair, it just depends where you are intending to use it as to how often it will need looking after and whether you want to!