And there's another way to do it. For nearly any country listed in the Scott catalogue, you can buy the latest catalogue pages on eBay
removed from the catalogue. There are sellers who do this . I add a title page to mine and staple them together so I can have them when I work on the appropriate album. I don't do this for all countries, obviously, but not having to heft an enormous catalogue, being able to move the set of pages around easily, and having a very recent set of pages make paying $5-15 for a set of pages for some countries worth it. It's possible to have up-to-date catalogue pages for a few of your favorite collecting countries for very little expense.
For my general set, I prefer a fairly recent set of catalogues. I buy them used since Scott/Amos' new catalogue prices are out of my league. For some countries, I collect recent stamps which is one reason I want recent catalogues. And catalogue descriptions, numbers, and research sometimes change. An older set of catalogues from 20 years ago might not even have the correct catalogue numbers. They also might be lacking important recent information I need to purchase the correct stamp. I was astonished some years ago to note in a new catalogue I'd just bought that in my 50 year old Scott U.S. National album, for example, a number of very early stamps I'd never been able to afford (and whose blank spaces had always bothered me), were no longer even considered stamps! They were now thought to be "proofs". Oops! So they'd been decommissioned and given new numbers. What a nice feeling that was -- or I'd still be cluelessly looking for them. Even some modern stamps somewhat end up in the catalogue with non-consecutive numbers or minor "a" or "b" numbers they didn't have previously.
For me, those facts are reason enough to own fairly recent catalogues. When those catalogues are five or six years old, I'll replace them as I always have with newer used catalogues. It's possible not to pay a lot for each volume if you're patient enough.