“Ako ay nagpapagupit kapag/pag mahaba na ang buhok ko” or “Nagpapagupit ako kapag/pag mahaba na ang buhok ko” means “I have a haircut when my hair is already long”. “Pag” is just the short version of “kapag”. You may use either one as they mean exactly the same thing. Joshua's answer is correct and is the most common way to ask a barber to give you a haircut. If you'd like to know how much it would cost, you ask, “Magkano ang gupit?” (How much is a haircut?)

When you want to get a haircut, you say, magpapagupit po ako. Kapag and pag are the same

do you want to learn tagalog ?

It seems to me that the "ako" in this sentence acts as what they call in linguistics, a 'topic'. If you know Korean, Japanese or Chinese, you might know what I'm talking about because they use it very frequently and in fact have special particles for marking them for the former two. Anyway, it's used to introduced a new, well, topic to talk about, especially if the context has a previous different one being talked about. The sentence might translate to "(As for) Me, I get my hair cut whenever it's long" which implies that "I" was not being talked about before this. It is not necessarily the subject, but in this case, it is also implied that it is, although it is actually not in the sentence structure. ("Ako" has to be after the verb "nagpapagupit" in order to be the actual subject in the sentence, but maybe because of redundancy, "ako" as a topic is sufficient to say). You can also say "Ako, nagpapagupit ako kapag mahaba na ang buhok ko" which is also the same thing but there is an actual subject in the sentence.

Hi Maksim. Not sure if you got the answer you wanted. I learned before that 'nagpa+ prefix has the meaning of 'allowed to be done+'. So your question is not a question or request, it is a statement which means what Evone said. But that is why Ako is in your statement - YOU allow your hair to be cut whenever it is long'. It is not the act of the barber cutting it :) It would be translated to english as 'I get a haircut'.