Man, when you’re playing multiple venues and don’t know what you’re going to be walking into in terms of PA, FOH speakers, monitors, walls, floors, ceilings, electricity supply, distance of cable runs, etc etc you really learn to take things into your own hands, to take responsibility for some of these variables so you don’t get stuck with hope, prayers, swears, or alcohol as your strategy for making it through the gig alive.
Show up with more than you need, and that reduces the unmet needs you’ll have on the gig. More wattage, more speakers, more cables, more basses, more power bars, more extension cords, more picks, more batteries, and so on. Bring a digital mixer so your IEMs and FOH can be the sound for the evening, but also set up your amp and cabs. If you’re very lucky, nothing will go wrong. If it’s typical, something will go wrong, and you won’t know what it will be until it happens, and hopefully you’ll have a redundant whatever it is to fall back on.
For sure - like I said elsewhere on TB, I played for decades with a 40 watt Traynor amp, and zero backup of anything. It’s possible, it’s doable. I also didn’t have gigs that I took seriously. Now I take every gig seriously, and that’s reflected in how I prepare. I also sound and play 100x better than I ever used to.