Present perfect

We often use the adverb ever to talk about experience up to the present:

My last birthday was the worst day I have ever had.

and we use never for the negative form:

I've met George, but I've never met his wife.

Remember the difference in use:

for a period of time (for ten minutes, two days, nine weeks, 100 years etc)

since a point in time (since I was a child, yesterday, my birthday, Tuesday, 2010 etc)

How long have you lived in Seville?
  For four years / Since I was ten / Since 2014 / All my life / My whole life.

How long have you been in this class?  (I’ve been in this class) for a year / since 2019.

We’ve played chess since we were about seven years old / for about nine years.

We use have/has been when someone has gone to a place and returned:

A: Where have you been?
B: I've just been out to the supermarket.

A: Have you ever been to San Francisco?
B: No, but I've been to Los Angeles.

But when someone has not returned, we use have/has gone:

A: Where's Maria? I haven't seen her for weeks.
B: She's gone to Paris for a week. She'll be back tomorrow.

We do not use the present perfect with adverbials which refer to a finished past time: yesterday, last week/month/year, in 2017, when I was younger, etc.

I have seen that film yesterday.
We have just bought a new car last week.

but we can use the present perfect with adverbials which refer to a time which is not yet finished: today, this week/month/year, now that I am 18, etc.

Have you seen Helen today?
We have bought a new car this week.

We often use the present perfect with adverbials which refer to the recent past (recently, just, only just) or adverbials which include the present (so far, until now , up to now, ever (in questions), yet (in questions and negatives): 

We have just got back from our holidays.
Have you ever seen a ghost?
A: Have you finished your homework yet?