Space Cadet's got it right, you should be able to measure your collection by the
meter!
I personally think the answer to the original question is that your collection should always be growing/expanding. If someone has 2000 albums, but hasn't bought any in 5 years, then I'd say something's wrong. Someone else may have 500 records yet actively buy one a week. I'd say the latter is a bigger music fan.
To me, any music fan is consistantly buying music.
Thirdly its an investment I am a pretty shrewd and knowledgeable second hand record buyer and my collection reflects this, it is worth at least 4-6 times what I paid for it. A far better return than having the money earning 3.5% in a savings account, and useful too!
This is only true if you have your records properly insured! About ten years back, a friend of mine had his
entire record collection destroyed. His sister was over doing laundry when she "accidently" left an item of clothing in the tub and all the water from the washing machine overflowed on his entire collection in the next room. It wasn't discovered until the next day and every record and jacket were ruined.
Fortunately, his insurance company reimbursed him for all the records
at face value. However, he had many albums worth far more to collectors. Unfortunately, the many albums purchased as an investment were worthless.
Learning from that experience, I contacted my insurance agent and found that people who have record collections (or any collection for that matter) are subject to waivers. It doesn't cost any more on my policy, but I had to document every record I have of value. It took me several hours writing down the items of most value. My agent also suggested video-taping my collection as well as my entire belongings.
The biggest problem with verifing that you have music of high value is that most is bought second hand and there is little in the way of receipts.
I also now keep my collection in different parts of the home, so in case of a roof leak, fire, etc., only part of the collection is destroyed. Even though I know I'd be reimbursed by my insurance company, I'd be devastated emotionally if
everything was lost in one shot.
Ron The Mon