“a long time”…why is it countable?

Question

I've gone through many threads here trying to find the answer, but to no avail.

Cambridge dictionary states: We use time to refer to what is measured in seconds, minutes, hours and years as a whole. In this sense it is uncountable:

Ex: Children nowadays spend more time watching TV than playing. (spent many hours)

So my questions is, how is the meaning in the sentence above different from, say, "I've spent a long time doing that"? (spent many hours) Can't we say "much time" in that sentence?. Which would mean the same, but then it'd be uncountable.

I just can't understand why "time" considered to be "countable" in a sentence like that.

"I've been there many times" = on many occasions. Here, it's clearly countable. So it is in "I've played football for a long time", but we can't really say "I've played football for a long occasion", can we? Hopefully I'm not asking something stupid..

Answer 1

When we talk about the amount of time (number of hours/days etc.) required to complete something, time is usually uncountable.

But in expressions like a long time or a short time, the word time is used as a countable noun.

https://www.englishgrammar.org/time-countable-uncountable-noun/

We can use such a/an with a singular countable noun : "We had such a good time together".

On occasion, on three occasions, on several occasions, on the occasion of something, for the occasion, for many occasions etc. are idiomatic; but "for a long occasion" is unidiomatic.