Apollonia
I tend to reside more in the "Suck it up and do it anyway" camp. I feel that as readers, it is desirable to live up to a certain standard of service, whether or not we are professionals.
If you are doing it sheerly for fun, rather than as a professional, you can probably get away with reading or not as the mood strikes you. But if you do decide that as a general rule you don't want to do it when you're not in the mood, I would certainly warn people up front that the time and date might need to be changed at the last minute, so they don't get all excited and then find they aren't going to get a reading. (But realize that you will be disappointing people anyway, because many of them will be looking forward to their reading with great anticipation from the very moment you set it up.)
If you are planning to go professional at some point, it's probably good practice to stick with the times and dates you set, so that you can get used to reading when you don't really feel up to it. I've been reading nearly every Saturday and Sunday afternoon for the past four and a half years, and over that period of course there have been times when I didn't feel good, or times when I just thought, "Oh crud, I have to go in and read all afternoon, when what I really want to do is _______." But you go in and start to read and somehow the mojo comes back, and it's fine. (And often when I felt I didn't want to do it, that person would come in who desperately needed a reading that very day, and I was so glad I had made the effort.)
If you are doing it sheerly for fun, rather than as a professional, you can probably get away with reading or not as the mood strikes you. But if you do decide that as a general rule you don't want to do it when you're not in the mood, I would certainly warn people up front that the time and date might need to be changed at the last minute, so they don't get all excited and then find they aren't going to get a reading. (But realize that you will be disappointing people anyway, because many of them will be looking forward to their reading with great anticipation from the very moment you set it up.)
If you are planning to go professional at some point, it's probably good practice to stick with the times and dates you set, so that you can get used to reading when you don't really feel up to it. I've been reading nearly every Saturday and Sunday afternoon for the past four and a half years, and over that period of course there have been times when I didn't feel good, or times when I just thought, "Oh crud, I have to go in and read all afternoon, when what I really want to do is _______." But you go in and start to read and somehow the mojo comes back, and it's fine. (And often when I felt I didn't want to do it, that person would come in who desperately needed a reading that very day, and I was so glad I had made the effort.)