I have a 4 year old Frenchie, and shortly after I got him at 8 weeks of age, I moved to Breckenridge, CO to a townhouse that had 3 flights of stairs. When he was young he would go up them with very little help from me, but it was coming down that was the problem. He was scared of heights, and would often run to the very top only to whine and beg for me to get come get him once he was there. This continued on for maybe 5 or 6 months at the most, but then once he overcame his fear he was unstoppable. He's been running up and down stairs for over 3 years now, and does just fine. He only has a problem climbing something if it's too high, which happens occasionally when I take him walking in the Colorado mountains. Other than that he does fine, and loves to be up high where he can see everything since he's so short. I agree with the previous comment about intervertebral disc disease, hip dysplasia, and/or patellar luxation. These are all things to think about as the dog gets older, but I also agree they shouldn't stop you from getting a FB. They are a ton of fun, and I wouldn't trade mine for the world. Hope this helps!