You can certainly start off with more than one agent to see who you like. Kinda shop around. But once you sign a buyer agency agreement (at least in CO) that is who you work with. At that point you don’t even want to do your agent “a favor” by contacting a listing agent of a property you might like to ask questions. You will always want to go through your agent for any questions or setting up showings. Also be upfront with any agent if you are using other agents before your buyer agent agreement is signed. There are some agents that would prefer to just let you work with another agent instead of wasting their time.