The best way to get apostrophes right is to understand when and why they are used. There are two main cases –

 

• Using apostrophes to show possession
• Using apostrophes to show omission

Apostrophes and plural forms
The general rule is that you should not use an apostrophe to form the plurals of nouns, abbreviations, or dates made up of numbers:
just add -s (or -es, if the noun in question forms its plural with -es).

For example:
euro euros (e.g. The cost of the trip is 570 euros.)
pizza pizzas (e.g. Traditional Italian pizzas are thin and crisp.)
apple apples (e.g. She buys big bags of organic apples and carrots.)
MP MPs (e.g. Local MPs are divided on this issue.)
1990 1990s (e.g. The situation was different in the 1990s.)
It's very important to remember this grammatical rule.