I have them and probably everyone should, but after getting a warning last year for flares that were one day expired, I looked up what a boat under 6m requires. I am not going to argue with a peace officer over it but going by what I read, you don't have to have them if you are under 1 nm from shore, which I was at the time. Should have just advised me and saved the paper work.
I bought mine from Trotac. They pro-rated them to their expiry date.