In my country "thérapie brève" (brief therapy) is quite popular these days. This kind of therapy is not supposed to last more than two to three months and I think it's quite good because you have to establish goals from the get go and you are encouraged to be independent. There is no "well we'll see how long it takes" because sometimes I think that by being vague about the duration, some clients just end up staying in therapy just because they're attached and their therapist is as well (emotionally and financially). As for how common long term therapy is: thankfully psychoanalysis is slowly disappearing (although it is still quite powerful in countries such as France) and therefore clients who are told they NEED to spend 15 years rehashing their childhood are a rarity. I asked a couple of therapists I saw and they told me that usually the majority of their clients stay in therapy no longer than 8 to 10 months. It's rare when people stay in therapy for years. And of course some clients just show up for two sessions and then quit so this may skew the numbers.