"For a long time" is NOT countable. We never say "for three long times" or it would be countable.

Countable and uncountable can be quite tricky in English. For example, 'water' is a word which people always learn is uncountable. What about this sentence, then: "The boat went missing in international waters."? Hmmm.... very interesting... Instead, here are some example sentences. See if you notice a pattern, and try to make some similar sentences yourself. I have been learning French for 4 years. I went to France for 3 weeks last summer. I spent a long time living in France when I was younger. Unfortunately I won't be able to go back to France for a long time, I'll be busy with my new business. I have been to France 3 times since I left school. I went to France 5 times last year. I tried to speak French with a language exchange partner for the first time yesterday.

Your words are still appreciated, Michael! Sometimes I am too focused on minor details and lose happiness.

It's meant helpfully. I hope it reads that way. There are so many little "rules" that beginners* are taught which are misleading; English is not a very rule-following language, in use. Have a good day :) *Correction - I see you are not a beginner. My apologies. I still offer the same advice - but of course you should evaluate it for yourself :)

Thanks for your suggestion, Michael!