have vs have had

I have 2 years experience.
I have had 2 years experience.

Are both interchangeable?

Usually, yes.

In passing, shouldn’t it read “two years’ experience” or “a year’s experience”?
I mean, the apostrophe is paramount here, is that correct, Beees?

That reminds me of “for convenience sake”. I remember some people say it’s OK with or without 's.

This is possessive. I would definitely use an apostrophe or reword it to avoid this problem.

According to this, the British see some of these examples differently.

People seem to be increasingly letting sound rather than rules dictate their use of apostrophes. I know some who have chosen to treat a “z” as an “s.” I find that odd and would never do such a thing.

Teacher: Jan/2000 - Jan/2006 (6 years)
Business: Feb/2006 - at present (4 years)

I have 6 years teaching experience and 4 years business experience.
I have had 6 years teaching experience since February 2006.

Check it please

In such case all I’m worried about is to say “a year’s experience” and not “a year experience”.

XYZ, just place apostrophes at the end of “years” in each example.

In your last sentence, however, it is impossible that you could have had six years’ experience since 2006, four years ago.

Since using four years and 2006 would be redundant, why don’t you write “I have taught since February 2006”?

My only other question is why you are referring to the time from February 2006 onward as teaching experience. You have it under business. And in your first full sentence, you separate the two. Did you teach during both eras? If you did, more revisions may be required for clarity’s sake.

I agree with Mordan. Do you mean you have had 6 years’ teaching experience since 2000?

Thanks for clearing the doubts. Please check the following.

Teacher: Jan/2000 - Jan/2006 (6 years)
Business: Feb/2006 - at present (4 years)

I had taught English until January 2006.
I had been a teacher from January 2000 to January 2006.
I had been teaching English for 6 years.
I had 6 years’ teaching experience.

I have been a business man since February 2006.
I have been doing business since February 2006.

The first sentence is incorrect. Number 4 is the best option you have, but I would use “have.” You still have 6 years’ experience.

Both business sentences are correct, but I prefer the first.

Please note that resumes do not often use the past perfect or past perfect progressive. Both are usually used to refer to something in the past that happened before another past event. They are very useful in giving accounts.