I'm often asked the question, "When do use HAVE with verbs, and when do I leave it out?"
and I say that you needn’t memorise “tenses”; you only need to know what functions HAVE serves.
HAVE basically serves to show a predisposition towards a condition or circumstance we find ourselves in. I call it the "existential-have", because it is our experience of something [at the core of our being] which we choose to claim to be our own.
Just as we use have to show possession (“I have two children”), which we’d rather say than something more obscure, such as “I bore two children,” or “I bore a child twice” for that matter.
We use have because (1) it is simpler wording, and (2) because:
“it is my experience* and I carry that burden (or responsibility if you prefer) to this day, regardless of the time factor, of when exactly I gave birth.”
*experience can be individual or collective.( I am not a mother and never will be.)
Let’s take a different approach to the same concept:
“I did the grocery shopping” means “I bought what was needed for sustenance.”
“I’ve done the shopping” is more likely to imply to the receiver that you don’t need to shop because the speaker already has, and there it is.
The have means “this is the situation.”
(Note: Nothing to do with typical coursebook-based explanations like "the action is not yet complete", as many will explain away as the Perfect “tense”.
“Perfect,” as it's called, just means “that’s just as it should be, nothing more nothing less.”
(Sure, maybe it will continue—but, then again, doesn’t everything?
NB: English does not have a Future "tense". (Subject matter for a separate article)
As for HAVE used in the "Future Perfect", I'm of the opinion that it should be restricted to a past context.
No joke. It's called the Historical Future.
“By 1886 he will have gathered 16 disciples.” —whereby have describes achievement(s) of the man in question.
Avoid this structure with real future aspects, since all else is but speculation. 😉
Finally, the had in the so-called Past “Perfect” is a different matter—though, not entirely different; it basically denotes one action or event happening before an_other.
“I-did-this-before-I-did-that,” which will translate as “I had done [this] before I did [that].” (Apology here for using such a flat example) and only in cases, I underline, where we'd want to stress the importance of that first action over the second—that situation or that experience which we claim to be ours.
So there you have it. And now that you "possess" the insider message behind the word, what need is there for creating some fantasy term like "tenses"? For teachers to keep teaching out of textbooks? Teachers, I hope that's not your excuse...