Final T, glottal stop or not?

Hi again,
I'm so sorry, I should have read CalifJim's post about T's a little more carefully before posting.
I see that there's also a glottal stop after R's, so the t in "smart" or "cart" is held. I see that there's a glottal stop (but sometimes it's not complete) after L and N, for example in "count" and "bolt".
But reading that post I noticed that T's after other consonants are not supposed to be held. Is there really that difference? I always tend to hold a final T, completely after a vowel, and almost completely in pairs like CT, ST, NT, LT, etc.
Actually, I tend to hold most consonants at the end of a word, and I noticed Ann Cook (author of "American Accent Training") tend to do the same. There's an exercise where she shows that words like "cot/cod" and "heart/hard" are distinguishable by the vowels rather than the last consonant.
What do you gous think? Thank you

Hi,
thanks for the reply.
By "held" I mean "unreleased", and by "unreleased" I mean "not pronounced", that is, a glottal stop. That term ("held") is fequently used in the book who helped me improve my pronunciation.
Anyway, this is too complicated a subject to discuss in a forum. There are often many ways to pronounce the same thing, and much depends on the context in which they are pronounced (with words that follow, speaking fast or with an accent, etc.)
The problem is sometimes I start to wonder about things I'm not supposed to wonder about... I realized that the less I think of what I say, the more I sound good, and the more I think of what I say, the more I find myself stuck and wondering if I'm making any mistakes or not. I think that happens to most people here: how many times have you tried to answer a question that seems very simple at first sight, but the more you think of an answer, the more you get confused and then you are not sure of the answer any more?