If you're at all serious about this, you need to 1) find out what a PA is and does, and 2) get one. You might be able to "jam-out" some songs without one, but you cannot prepare a performance for more than a dozen people (and if that's your thing, enjoy!). You need to be building experience in what they can do for you and do to you.
For rehearsals, we don't mic anything but the vocals (though we use what used to be our show rig for rehearsals, monitors and all). For shows we mic everything. That makes for a much better show with much better balanced sound, regardless of the size of the venue.
As far as "old school", the Beatles did not mic their amps at Shea--though you can't hear them, either. A good lesson in how important proper support can be. It was really the Dead (pictured above, if I'm not mistaken), that really started the trend towards band-managed full-band PA support.
Get crackin'. You have a lot to learn.