What Are The Most Useful Tools For Identifying/Collecting

So I checked my local library for catalogues - their only set is a Scott's 2006 edition! However, they did indicate that the library is currently in the process of updating some of their reference books so they may be getting a new set. If so, they will hopefully sell the 2006 set for pretty cheap! It's not the Stanley Gibbons set that I want, but I just don't have the $90 to shell out for a SG set right now!

Agreed with all the above comments, but personally I do not like the SG catalog, period.

The only other tool that I did not see listed above, was alcohol--the drinking kind, like a single malt scotch whiskey.

It is essential for making this a hobby, and in a pinch as a watermarking fluid (not).