A spending cap (also called a not-to-exceed, or NTE) is the most you've agreed to charge a client. You set one cap per client. Every work order that client requests inherits that cap.
Setting your cap
Open the client's profile and set their Spending cap. That's it. One number. From then on, every work order that client requests starts with that cap already in place. You only have to do this once per client, and it stays put until you change it.
Setting a custom cap for one job
Sometimes a single job needs a higher (or lower) cap than the client's usual one. On the New Work Order screen, turn on Set a custom cap for this job and enter the amount. That custom cap applies to that one work order only. It does not touch the client's standing cap, so the next work order goes right back to the usual number.
Requiring a cap on every work order
In your settings you can turn on Require a cap on every work order. With it on, if a work order comes in without a cap, the requester is asked to set the client's standing cap or a custom cap before they can submit. With it off, work orders can go through with no cap, billed as time and materials.
If a tech tries to go over
TradelyHQ stops them and shows an error. They can't save the work order until the total is back under the cap.
Why this matters
Spending caps protect your relationship with the client. No surprise overages on the invoice, no awkward "why is this $3,000 when we agreed on $1,500" conversation, no eating the difference yourself. The cap you agreed to is the cap that gets charged.