Most people just don't care whether or not they put an apostrophe when it's needed [see, I just used one!], simply because they don't know IF they need it.

When should you use an apostrophe?

You should use an apostrophe if you are OMITTING a letter, in this case, "It is ..." gets shortened to, "It's" - you leave out [omit] the second "i", and it gets replaced with an apostrophe:

It's = It is = It has = It was

• It's [it is] raining men!
• It's [it is] a long way to Tipperary!
• It's[it is] just not fair - I should have first prize.
• I liked that movie - with all its adventure, It's [it is] going to be a smash hit!
• Isn't it a shame? Yes It's [it is] a shame we missed the train.
• It's [it has] been such a great week.

Its = Its *own* ... *no* apostrophe

When do you use "Its" without an apostrophe?

You don't need an apostrophe if you want to say:

(a) The cat licked its fur.

If you had an apostrophe in this phrase, you'd be saying:

The cat licked it is fur.

You don't want to say that, do you? No, I didn't think so.

(b) The briefcase and its contents were stolen.

If you put an apostrophe in this sentence, it would mean you meant to say:

(b) The briefcase and it is contents were stolen.

You don't *really* want to say that, do you? Of course not.

I hope this helps.

If in doubt, don't!

What do I mean by that? Well, if you're not sure, don't use an apostrophe.

You *only* need an apostrophe if you REMOVE or OMIT a letter in "it is"[or to show possession or ownership].