While it’s true verbal agreements can be legally binding (it helps if you have witnesses), the gold standard for contracts is the written agreement. This will make things easier in the event there are later discrepancies or disagreements around the terms agreed upon.
It’s also a way to protect both parties from misunderstandings or mistakes due to divergent memories of precisely what was agreed. It’s a known fact the human memory is far from infallible.
(I’ll never forget the time I showed up with my band at a club on a Saturday evening to find an irate Club Owner, furious with us because we were not there the previous night. I had very clear memories of multiple phone calls where we specifically spoke about Saturday, but he swore up and down we were supposed to play on Friday.
Needless to say, we never played there again. This fallout could have been avoided with a simple written contract.)
Some people in the industry will say a simple email with the details should be enough to confirm the terms of an agreement. While a date-stamped email is certainly better than nothing, in a case where there is a serious disagreement or accusations of wrongdoing, it can be hard to prove where the email originated, or that it was not doctored.
For all these reasons, I would recommend you never perform anywhere without a written contract or agreement. Even if there is no money involved, there should be a written “confirmation” or agreement where all details and expectations are laid out clearly. It’s the safest and wisest way to proceed.
It’s important to understand that the best contracts protect both parties. This might be worth mentioning if you are ever asked by a client why it is necessary to have a written contract. It’s not only about trust, it’s also about clarity.
A contract exists to protect both parties. There really aren’t any one-sided contracts worth the paper they are written on. Why would anyone sign an agreement that only protects one side? It’s smart to always try to point out to a counterparty how a contract will also protect their interests.