Standard 30 day terms feel normal. They also mean you do the work, pay your people, pay your suppliers, and then wait a month to get paid. You're not a supplier at that point. You're a lender.
Payment terms decide who carries the project's cash gap: you, or the client. Let's watch the same job on four different terms.
A £50,000 project. Your costs to deliver: £30,000, paid as you go.
Immediate or upfront: the client pays before or as you deliver. You fund almost nothing.
30 days: you carry the £30,000 of costs for about a month before the £50,000 lands.
60 days: same costs, carried for two months.
90 days: three months of funding someone else's project out of your own bank account.
Same profit on paper every time. Completely different pressure on your cash.
Every extra day of terms is another day your cash is tied up, another day closer to payroll, another day of risk you're carrying so the client doesn't have to.
Upfront or staged payments flip that. A deposit funds the start. Milestones keep cash arriving as the work does. You deliver from the client's money, not yours.
But everyone offers 30 days." Common is not the same as sensible. If a client needs flexibility, that's fine; just don't fund it yourself. Offer a deposit, offer milestones, or point them to third party financing. Support the client. Don't bankroll them.
Ask for a deposit as standard. Bill in stages. Shorten terms where you can.