Is there a difference between 12 months and 1 year?

There is a difference and the exact meaning would depend (as usual for English) upon the context!

12 "contiguous" months = 1 year and, in general usage, if you say "a year" it is taken to mean a "calendar year" January-December. But "a year" is also the time span between February 20, 2013 and Feb 20, 2014 (or any other equivalent.) Generally, if you are speaking of anything other than "a calendar year" you would use 12 months. In many financial transactions it is important to specify "the months".

Special note: I learned on my first job something that had not come up in my college education. If you are earning $400 per month, that is not equal to $100 per week! That is because only one month (most of the time) has exactly 28 days or 4 weeks and the rest have either 30 or 31 days. There are 52 weeks in a year, but not exactly 364 days! A month averages 4.333 weeks so $100 per week is actually $5200 a year and thus $433.33 per month.

Because a nit picker can try and claim a year is January to December, rather than a twelve month period.

You'll also find that documents which use months are often doing this because it allows them to change the time frame easy switching twelve for twenty-four. or six.

A calendar year has twelve months

A lunar year has 13 months

So a year could be 12 or 13 month unless you specify which type of month you are using; which is why estate agents often use the term "per calender month."

1 year is NOT necessarily 12 months. Who is to say that the 12 months are CONTIGUOUS. I can say I use a summer home for 12 months...4 months at a time in three years.

There is no actual difference because 30 days = 1 month and 12 month =1 year=365 days . for be month we need only 30 or 31st days but to be year it needs 365 days i.e 12 months.

The term months might be used where payments are to be made monthly. Other than that I can't think of what problem would be avoided by using one term rather than another.

Starting from first day of any month,proceeding forward, up to the last day of immediately preceding month is a period of 12 months or one year.

There's no difference, personally I think it's just a matter of personal style.

No, its the same amount of time, people just express it in different ways,some lawyers when a contract is involved say 12 months.

It is the same.