Class A's may be a dept issue for many career depts. Most of the career depts here, class A's are issued as part of the uniform allowance or after the probation time is completed. Many volunteer depts don't invest in class A's, but there are some of those who did purchase their own set.
I agree with Chris with a nice set of class B's which will suffice for most occasions and still looks professional. I would wait on buying your own class A's (assuming they are not a dept issue) unless you know where you want to be and quite sure in your career path.
John, is right most if not all career dept. issue class A uniforms. Around here there are even a large number of Vol. dept. that also issue class A uniforms.
With larger career dept. the chances to wear the Class A does increase. We have dept. or union functions etc. I know of a couple Vol. dept. near Indy that have a couple formal balls during the year.
You might think about talking with people on your dept. if you get enough intrested you may be able to get a deal on Class A or B. Another reason is if you get a set of class A's then later on another member get's a set. The problem you run into is that there not all the same,there are diffrent styles, colores, number of buttons etc. So unless your dept. has a defined Class A Uniform code. You could have a group standing together with the same dept. patch. But looking like they just fell off a goodwill truck.
Just food for thought.
My FD invested in Class A uniforms about 10 years ago.
They have been the topic of lots of discussion, just like yours.
However when we are at a Formal Function or a Funeral - they are worth every penny.