By Chanelle Bessette | NerdWallet If you’ve ever lived off of tips or commissions, you may be familiar with the up-and-down paychecks common in certain industries. Service jobs, sales jobs, creative careers and project-based work can all have fluctuating income, where seasonality, events or the general economy might affect your earnings. When you can’t depend on a regular paycheck amount or paycheck timing, it can be hard to know how you’ll make ends meet when money isn’t as abundant.