The longest drama i've seen has 150 episodes, the Pink lipstick.
It depends on where i watch dramas, if it really caught my interest and it has too many episodes, i always buy DVD copy of it then watch it time to time.

But if its less than 50 episodes, i watch it online.
The number of episodes doesn't matter to me, as long as it is tolerable, enjoyable and still giving me benefits, i will definitely finish it.
I don't have an amount but if it longer than 30 episodes I'll allow myself to take a break from it for a month or two.
The longest Asian drama I've watched was 60 episodes, so I think somewhere around that number if the episodes are regular length. If they are shorter I could watch a longer one, like in the case of Gu Am Heo Jun. It would be around the same as watching a 60 episode one.
I prefer watching dramas with episodes under 24 episodes usually, but if the story line is good i don't mind how many episodes there are. Longest drama i've watched is you are my destiny with 178 episodes, not sure how i managed to do that :/
Apparently I don't have one. I watched one that was like almost 200 episodes but it was good! Sadly, I don't recall the name but it got me through college. I think it was a Kdrama.... I also will watch long Japanese ones because those are so rare and I like to support them. Ohisama had 150 episodes I think.
I tried to avoid watching anything over 24 episodes. I have made exceptions to this rule though and gone for things that were 50 episodes. These exceptions are few and far between. I honestly don't have the patience to deal with dramas that are too long. I normally find myself sitting there going, "are these people still arguing over silly stuff? That's it, I'm done. Time to drop this thing and watch a variety show instead."
I don't have one. I don't dropped drama so even if it's 100 episodes up...I will finish it. If I found it slower in the middle I just watch little by little episodes until I'm done with it.
I am not unwilling to watch 50 episode dramas as long as they are interesting enough. 70-100+ episode dramas seem a bit much. Wouldn't stop me from watching if I was truly interested in the plot though...
I really prefer to keep things under 20. The reason I like Asian Dramas is because they are watchable in a few sittings if not in one night. So too many episodes kind of negates that point for me. :)
My limit is 20 - 24, longer dramas seem like a waste of time for me.
Right now the longest drama i watched had 159eps (Smile, Dong Hae), when i was still into watching telenovelas i was watching the series that had more than 200 or even 300eps so i don't thnik i have any limit, if the drama is interesting the number of eps doesn't matter.
The longest I've seen so far is up to 60 eps but if the drama is good I can go longer.
I don't think I have a limit. The longest drama I watched was like 50 episodes. And there's some other longer ones I aspire to watch. It all depends on how much time I have, my mood, and how good the drama sounds. I don't really write a drama off for its length though. (: