TMIDI is right! You just can't go by listening only.
The reasons I'm going to give are theory based, but you'll see why seeing and hearing should be used in conjunction.
Note: This isn't a Sight-Reading vs. Play By Ear argument; however, there are downsides to both:
Here's the issue with Sight-Reading: You'll play and read fine with the page, but take it away and it just sucks (to be blunt) lol
Here's the downside to Playing By Ear: Enharmonics.
By ear alone, they don't matter, but the minute you start to write down the chords - or better yet: if you were to hear a piece in B (which has five sharps), but pick up the sheet music and it's in Cb (seven flats).
It's still not really an issue because one or the other is chosen for a number of reasons:
Pianists don't play in Cb, because they can play in B just as easily and five sharps don't bother them (seven flats may not bother them either, but there will be tons of accidentals in the music.)
The same is true with C# though seven sharps may not bother them as well. Take Chopin's Fantasie Impromptu - starts in 4 sharps, but ends in 7 sharps.
Now, when evoking enharmonics, we run into a problem ...
While five flats and seven sharps are okay, with Fb/db: we're dealing with eight flats (BEADGCF and B). Plus, there a double-flat when the scale is written
The other reason is instrument structure (not just the physical, but the acoustics). For example, the harp sounds better in flats keys than sharp keys since no pedals are engaged (all of them up) This is why is tuned to C-flat and the music is written in C-flat. The music may be written in B, but if it is, it'll be played in Cb cause it's easier on the instrument.
Db rather than C#, Gb rather than F#. OTOH. you just have to put up with D, G and A
Of course, this is up to the performer, but composer must at least consider it.
I realize I went off topic, a bit, but again, I do agree with TMIDI on getting the songbooks.
Yet, if these are your own tunes, it makes no difference what you call the chords (enharmonically speaking) - when written out - for you or someone else to play, however, it will matter.