Whether you allow your pets on your furniture is a personal preference and totally your business. It is, however, something you should consider when you're choosing your furniture.
If you do anticipate that your pets will be on your furniture from time to time, you should definitely choose carefully. I have only owned one leather couch in the past and my cat totally destroyed it with his claws! He seemed to enjoy using the couch as his "launching pad" to attempt to jump onto the top of my bookshelf, and thus my couch was eventually covered in scratches/gouges from him "taking off", lol.
My parents have also owned several boxers, which are rather large energetic dogs, and have had to really train them not to get up on the leather furniture as they did have a couple of incidents early on with the dogs puncturing the leather with their nails.
On the other hand, however, I do find that the leather is much easier to clean. It does not attract pet hair the same way that fabric does, and it is much easier to wipe up spills, etc.
You know your lifestyle and/or your pets better than anyone. I think the best advice is to try to think logically and reasonably about what is going to work best for you and do your research on any potential furniture you may be interested in.
Good luck ... hopefully you end up finding something you are really happy with! :woot: