I've done IEM with a big amp for a while. Our drummer, who was reluctant to swap over, was the only one without IEM. I thought I needed the flapping of pants and shaking of floorboards my big rig supplies so well. Then, at one point we started a song during rehearsal and just after the firs chorus the drummer stopped playing and looked at me. I asked why he stopped and he asked me if anything was out of the ordinary. I could not guess what he meant, everything was just fine - until he pointed out that my amp was on mute. Everyone had the bass on IEM, only the drummer had none at all. I did not miss the flapping pants and the back massage. I just did not notice their absence, IEM had me immersed in the song too deep. So when we got the drummer to get a pair of earbuds, I switched to a small amp - just for appearances sake, and then to no amp at all.
My entire IEM
setup(earbuds, custom molds, transmitter + bodypack, Headrush Gigboard; total cost roughly 1500)
cost me quite a bit less than my
normal rig (Aguilar Tonehammer500 or Ampeg PF50-T, Barefaced Super Midget, Barefaced Super Compact, small pedalboard with essentials [tuner, comp, OD, reverb]; total cost roughly 2700)
But I actually came to prefer those gigs where I leave the rig at home and travel light.
However - for the time being I could not imagine myself without owning some means of amplification that can hold its own against a hard hitting drumer and a guitar halfstack.
I guess it has to do with where I came from and how it was playing live back in the days when I was young and FOH was for vocals and bassdrums.
I've come quite a way already from the state of mind where I always brought a powerful rig (I can turn it down if it's too much) to my present state where it's important to have such a rig when needed, but it's actually quite the rare occasion where it sees some use.
Will I ever ditch that and not have a potent rig at all? I can't answer that.