it is advisable to have a selection of harmonicas in different keys
otherwise you'll be limited to playing along with only things that are in the key to which your harmonica is complimentary.

for instance, song in E would want an A harmonica

unless you've not gone for diatonic ones. In which case ignore what I've said
( Vipros. clever got me this far, then tricky got me in, Tue 24 Nov 2009, 12:07, 2 replies, latest was 17 years ago)

Or...
...just get a kazoo.
(Tugnut Ex of this parish, Tue 24 Nov 2009, 12:11, Reply)

Well
I'm mainly wanting to learn the basics but having played guitar for about a decade now I'm fairly familiar with changing key to suit my needs. One day would like to have a few harmonicas but I hear the key of C is the best for starting out...
( whenanimalsattackhumans clad in global hypercolour, Tue 24 Nov 2009, 12:15, Reply)

well, the harmonica player in my band has about 10 for various keys
we play blues type stuff (and he plays dylan-type stuff) and generally for that a C would be suitable for songs in G
( Vipros. clever got me this far, then tricky got me in, Tue 24 Nov 2009, 12:23, Reply)

it took an embarrassingly long time to work that out
I had just the one harp and got reasonably good on it but couldn't fathom key variations. I love a good harmonica player, but fucking loathe that Dylan-style asthmatic bagpiper style. My fucking gran could master that in about two minutes.
( Monty Boyce, My cheese game is strong, Tue 24 Nov 2009, 13:34, Reply)