How to address "we need to bill for this"

I get calls from clients who I think expect free time...How do I discuss that I need to bill for time. For example someone called and wanted a lot of info on child retirement planning, setting up parents retirement planning, child tax issues...I spent half an hour on the phone and then another 2 hours research and putting a memo together...and all withing a day. I did not say upfront I need to charge..will the cliient see value in this? and how do I say it?

great information.

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