By not using credit cards, you're giving away 1–5% free reward money from cash back programs. Not to mention the additional purchase protection you receive from shoddy vendors, like bars padding tips.
I've never felt like it's taken much discipline for me personally, and I've never carried a balance on any credit card. I try to live far under my means and mostly just spend money on food, coffee, travel, and a laptop. Most of the rest of my "things" are hand-me-downs.
One "hack" that works for me is reviewing each transaction and paying the card in full every week. If I see it especially high one week then I spend more conservatively the next. I don't do any explicit budgeting, but being conscious of the big picture helps me.