[Service type]=2 AND
(year([Last Service])<year(Today()) ), true, false
This will look at the year part of the [last service] date field and compare that to the current year.
The Today() function is dynamic and changes every day.
The Today() function has open and closed parens. the two extra right parens close the Year() function and close off the comparison statement.
Today() is also just a date function. Now() is a date/time function.