The realistic position is that a template is considerably better than nothing, which is what most first year businesses actually have. An engagement conducted on a verbal understanding and an email is where the expensive disputes originate, and a flawed written agreement resolves more of them than no agreement resolves.
What templates reliably get wrong is specificity. A generic services agreement describes a generic service, and the section defining what you are actually delivering is either blank or filled with something approximate. That clause is where most disputes live, and it is the one part a template cannot supply.
Check the jurisdiction, since templates are frequently written for somewhere else. A document referencing the wrong state's law, or containing provisions that are unenforceable where you operate, is a document that will not do what you expect. Consumer protection in particular varies enough that a clause valid in one place is void in another.
Read for what is missing rather than only what is present, which is the harder task. A template covering payment and confidentiality thoroughly while saying nothing about who owns the work has omitted the clause that causes the most expensive surprises. Absent a written assignment, the person who created something retains the copyright, and a template that does not address it leaves that default in place.
Watch for provisions that do not apply and remove them rather than leaving them. A contract containing clauses about employees you do not have, deliverables you do not produce, or processes you do not follow reads as unconsidered, and it creates ambiguity about what was actually agreed.
Be careful with anything one sided, since many templates are written from one party's perspective. A supplier agreement downloaded from a source that sells to buyers will favour the buyer, and using it as your own contract means agreeing to terms nobody negotiated with you.
Get the important ones reviewed rather than every one. A first client agreement that you will reuse fifty times is worth an hour of somebody's time, because the same clause repeats across every engagement and a flaw compounds. A one off arrangement for a small piece of work does not carry the same case.
Then adapt it and keep the adapted version rather than starting fresh each time. The document improves through use as situations arise that it did not cover, and a contract refined across ten engagements is considerably better than a template used ten times. This is general information rather than legal advice, and anything with substantial money attached deserves professional review.
Have the other party's version reviewed rather than only your own, since the contract you sign matters more than the one you send. A client agreement arriving from a larger organisation is written in their favour by default, and the clauses worth checking are indemnities, liability, and what happens on termination.
Keep every signed version rather than only the current template, because the agreement that governs a past engagement is the one in force at the time. Filing the executed copy with the client record takes seconds and is what you would need if anything is ever disputed.
Test it against the last engagement that went wrong, since that situation tells you which clause you actually needed. A contract improved by real experience is worth more than any template refined in the abstract.