The following chart details the Fender serial number schemes used from 1965 to 1976.
You will notice that there is quite a bit of overlap of both numbers and years.
The Fender company has gone through three major periods or eras in its existence.
Collectors value instruments based on a number of factors.
(If you are not comfortable performing this operation, please use an experienced professional guitar tech in your area).
The serial numbers do not immediately reflect the change, as CBS continued to make instruments using existing, tooling, parts, and serial number schemes.
A 1964 instrument can be worth 25% more than an instrument from 1966.
So knowing what you have can affect the price from a few hundred to tens of thousands of dollars.
The only way to try to narrow the date range of your specific instrument would be to remove the neck and check the butt end of the heel of the neck for a production date, which may be stamped or written there.
The neck date simply refers to the date that the individual component was produced.
Given the modular nature of Fender's production techniques, an individual neck may have been produced in a given year, placed in the manufacturing warehouse and remained in stock for a period of time, and then subsequently paired with a body to create a complete guitar in the following year.
There is a new issue every year that reflects current trends.
But if you are a casual observer you don’t need to buy a new one every year.