Deciding how to share household costs when incomes are quite different

My partner and I earn quite different amounts. A strict 50/50 split leaves one of us with little discretionary money, while the other saves comfortably. We're considering splitting shared bills proportionally to take-home pay, while keeping individual accounts for personal spending. How have you handled changes in income without turning every bill into a discussion of fairness? I'm interested in simple systems we can revisit occasionally rather than constant recalculation.