Apparently the hardest part for beginners is changing between chords.  I can assure you, this rumor is correct.  The callused fingers are nothing compared to trying to get your left hand moving quick enough to catch up to your right hand.  Justin guitar has an exercise called One Minute Change where you set a timer for one minute and see how many times you can go between two chords.  The goal is to switch chords 60 times in 60 seconds.  This takes time and practice to get to; most people start with about 15 changes in a minute.

I start off with D and A, set the timer on my phone and start counting.  It doesn’t sound quite as pretty, but I get through 29 changes in a minute.  Nice for the first try!  I switch to D and E and then E and A and get through a similar amount of changes.  Now I can switch between chords!  Now it’s time to learn a song… but wait!  It’s almost the end of the month!!  Nooooooo!