A T&M ticket is the record of work done on a time and materials basis: the hours by person and rate, the materials used, the equipment on hire, signed by somebody with authority on the day the work happened. It exists because the work sat outside the agreed scope, which is precisely why it is challenged later. Almost every dispute about a T&M ticket is about the signature and the date rather than about the arithmetic.
Get it signed on the day, by somebody who can sign
A ticket signed at the end of the week by whoever is still on site is worth a fraction of one signed at the end of the shift by the person who instructed the work. Write who instructed it and when. If nobody with authority is available, note that on the ticket and send it the same day rather than waiting.
Hours, materials, equipment, and the reason
Each person and their hours at the agreed rate, materials by quantity with the markup basis stated, equipment by the hour or day, and one plain sentence about why the work was outside the scope. That last line is what converts a ticket into a variation rather than a bill somebody can characterise as your own rework.
Number them and reconcile before you invoice
Tickets are numbered, kept against the job, and totalled before the invoice goes out, so the invoice cites ticket numbers rather than a lump. When the client queries the total the answer is a list of numbered, signed tickets, which is a short conversation, instead of a claim assembled from memory, which is not.
Questions people ask about t&m tickets
What does T&M stand for?
Time and materials: work billed at agreed labour rates plus the cost of materials and equipment, rather than for a fixed price. It is used where the scope cannot be defined in advance, which is usually discovered conditions or client changes on site.
Should a T&M ticket show rates?
Show the hours and the agreed rates if the contract sets them, because a ticket that shows hours alone invites a later argument about which rate applied. Where rates are commercially sensitive, state the rate schedule the ticket is drawn against.
What if the client refuses to sign?
Record the refusal on the ticket with the time and the name, send it the same day in writing, and keep working to the instruction if you have one. An unsigned ticket sent contemporaneously is far stronger evidence than a signed ticket produced a month later.