The practical situations where it matters are narrower than the general anxiety suggests. Financial details, customer lists, unreleased products, proprietary processes, and anything you are contractually obliged to protect on somebody else's behalf. Those are worth an agreement. A description of your business model and your marketing problems generally is not, and requiring one before a first conversation slows things down for no benefit.
Send it early if you intend to use one, because the awkward version of this is asking somebody to sign after they already know the thing. An agreement covering a conversation that has happened is considerably less useful, and the request arriving late implies a concern about the person rather than a routine process.
Read it before sending rather than using a template unexamined, since mutual and one way agreements differ meaningfully. A one way agreement protects only your information, which is appropriate where only you are disclosing. A mutual one protects both, which is usually more accurate since a provider will describe how they work and what they have done elsewhere.
Watch the duration and the definition, which are the two clauses that matter most. An agreement with no end date is unusual and frequently unenforceable, and something between two and five years is typical. The definition of what counts as confidential should be specific enough to be meaningful, since an agreement covering all information exchanged is difficult to apply.
Understand what it does not do, because expectations here are frequently inflated. An agreement does not prevent somebody working with a competitor, which requires a separate and considerably more contentious clause. It does not prevent them using general knowledge and experience gained. And enforcing one requires demonstrating both a breach and a loss, which is expensive and rare at this scale.
The practical protection is largely behavioural rather than legal. Sharing what somebody needs to do the work rather than everything, granting access to systems rather than exporting data, and removing that access when the engagement ends. Those do more than any document, and they operate without anybody having to enforce anything.
Expect a straightforward yes from anybody reasonable. A provider objecting to signing a standard mutual agreement is telling you something, and the objection is rarely about the document itself. Equally, a provider proposing one of their own is normal rather than suspicious.
Then keep a copy somewhere findable, since agreements signed at the start of a relationship are exactly the documents nobody can locate two years later when a question arises. Filing it with the engagement rather than in an email thread takes seconds.
Consider whether the concern is confidentiality or ownership, since those need different documents. An agreement about keeping information private does nothing about who owns work produced during an engagement, and businesses frequently sign one believing it covers both.
Use a plain document rather than an elaborate one, because an agreement nobody read protects nobody and a long one from a template describes situations that do not apply. Two pages covering what is confidential, for how long, and what happens at the end is sufficient at this scale.
Check whether you are already bound by one, since businesses working with larger clients frequently have obligations they have forgotten. Sharing a client's confidential information with a provider without permission is a breach regardless of any agreement you sign afterward.