The activities/leadschanges endpoint "Returns a list of Data Value Changes and New Lead activities after a given datetime", as the documentation says: (http://developers.marketo.com/rest-api/endpoint-reference/lead-database-endpoint-reference/#!/Activi...
That seems to mean that a Lead has been run through some activity and that some of its values has been updated. My question is: Does it means when that happens that the Lead has been updated? Can we say it?
A lead has a creation date as well as an updating date. The updated date of a lead, should match some row in the activities/leadschanges results. Is that a correct asumption?
What I'm trying to do is getting just the leads that have been updated in a time range. So, I request getLeadsChanges endpoint for that time range, extract the lead IDs and ensure they are unique, and then I query those lead IDs to get a bigger picture of them. Does it make any sense?
It is unlikely you will get a quick answer if you post your questions to the champion program group instead of the product group. Read this: Getting the most of the community when you have a Marketo question
Yes, the "update" date will correspond to a "data value changed" activity log.
And yes, your approach makes sense, although you can also use the get paging token endpoint to start at a specific date the retrieval of the activities.