The problem is not the size of your income, it is the variance. And variance is fixable even when income is not. Separate the account money arrives in from the account you live from. All earnings land in a holding account. On a fixed day each month you transfer one fixed amount - your salary - to the account you actually spend from, and you live on that figure regardless of what the month brought in.

Set the number honestly. Take the last twelve months, discard your two best months, and use the average of the rest, or simply take your median month. Start lower than feels comfortable, because the first few months are the hardest: the buffer is thin and one bad month can break the system. Once the holding account carries two months of salary, the whole thing becomes self-correcting.

This is smoothing, not saving, and the distinction matters. Saving happens after the salary, from the spending account, like everyone else. What smoothing changes is psychology: a bumper month stops feeling like a celebration and starts functioning as a deposit into your own payroll. It also makes school fees, tax and family obligations plannable events rather than recurring emergencies.