For the most part, I only add series to my watched list that I know I've watched every episode of, but lately I've been thinking of adding series to my list that I watched a while back on TV. The reason I haven't added any of them though is that I can't be sure if I've actually watched all the episodes...
So I'm curious. Do others here add series they saw long ago on TV even if they don't remember seeing every episode or even finishing it?
I've done that to some degree. My best advice is to round it off to easy numbers based on your best judgement. In the case of Pokemon, I had quit watching that around the time they moved to Johto. I looked up the episode list on Wiki and just went with the number of episodes up to that point minus the ones that didn't air in America. Try looking up a detailed episode list of the shows in question and stop when the episode descriptions don't sound familiar anymore.