Naming your workflow runs
A run's name is how you find it again. Get it right when you start the run and you will never have to hunt for it.
Name it after the thing it is about
The workflow name is already attached, so do not repeat it. Name the run after what makes this one different: the customer, the property, the invoice number, the person being onboarded.
A Customer Onboarding run for ACME Co. is named ACME Co., and appears in the list as ACME Co. - Customer Onboarding. Naming it "Onboarding" gives you a page of identical rows.
What happens if you leave it blank
The run takes today's date. That is the right answer for anything that recurs on a calendar, where the date is the distinguishing feature, and the wrong answer for anything driven by a customer or a case.
Recurring runs
For a scheduled recurring run, leave the name blank in the schedule and each run is named with its own date. Putting a fixed name in the schedule gives every run in the series the same name, which makes the series unreadable.
Naming for search
Run titles are searched by global search and by the filter on the Runs page, so a consistent naming habit pays off across the whole account. If you deal in reference numbers, put the number in the name. If you deal in people, put the name. Pick one shape and stick to it.
You can rename a run later from its settings, and it is worth doing the moment you notice a run you cannot identify.
Video walkthrough
This video walks through naming your runs.