Good question and one I really worried about when I first started freelancing two and a half years ago. In that time I’ve charged by the day, by the hour, by the month and a project fee. It also depends on the nature of the project such as whether it might lead to more work, how interested I am in the project either due to the subject matter or the specific challenge involved or whether it will add a different dimension to my skillset/experience. If it’s a start up or a not-for-profit then might charge a bit less or over-service the account a bit to add value .
I had a conversation early on with another friend who freelances and realised I was undercharging in some instances.Generally, I either get approached and told what they’re offering as part of the initial conversation or I’m asked what my day/hour rate is. I’ve had a few clients who are late payers so I try to bill for the first month when I start the project with payment requested within 28 days. Admin and chasing people for money is definitely the worst part of my job alongside doing my tax return .