A good reason to document your observations:

I wanted to share an article concerning an observation I made on April 20, 1993.  It’s a testament that documenting and taking good notes is indeed a good thing!    

Forward to February 1994: 

While reviewing my logbook, I discovered that I’d not followed up on an object viewed on 20 April 1993.  The primary object was NGC 3893, an 11th magnitude galaxy in Ursa Major.  While making my sketch of this galaxy, I had noticed a smaller much fainter object SE of NGC  3893.  

I noted this in my logbook to check later, however, it would be ten months later (February 1994) before going back.  So, while browsing through my logbook, I saw my notes that said:  follow up on this observation. 

I checked Burnham’s Celestial Handbook, Tom Lorenzen’s 1000+, and the Tirion Sky Atlas 2000.0 only to find that none of these sources listed a companion galaxy.  I then went to the NGC-2000.0 Catalog by Roger Sinnott, and found the companion listed as NGC 3896, a very faint and small 14th magnitude galaxy.  

So, If I had not sketched NGC 3893, most likely I would have missed NGC 3896.  And, if I had not logged the companion, I probably would never have checked any reference material.  

This might be a good story for documenting, taking good nights of your observations, and periodically review that logbook.  You never know what you may find? 

The following sketches:  

The first being my most recent sketch of the galaxy pair, which was made in April 2014, and the second is my original from April 1993.  It was on this night that I questioned if I was actually seeing another galaxy, ESE of NGC 3893.  

Roger Ivester