The agreement spells out what the agent owes you: undivided loyalty, confidentiality and full disclosure of anything that affects your decision. Without it in writing, an agent showing you homes may be working for the seller instead, which changes whose interests come first at the negotiating table.
Some brokerages ask for a signature earlier simply to formalize the relationship before investing time in a search. That is a business preference, not a Saskatchewan requirement, and the terms, including how long the agreement runs, often 60 to 90 days, are negotiable.
Read what you sign and ask what happens if you want to switch agents. Get your hand-reviewed valuation from Joel Dyck.