The health line on a lead is an excellent way to identify which leads need a follow-up/require action to be taken. The health line of a lead can be found on each lead in the funnel view, as shown below.
Additionally, you can hover over the health line to see the definition of the colour.
The colours indicate the following:
Grey: The lead is fresh
Red: Lead has not been updated in 30 days
Orange: There have been no updates in the last 10 days
Yellow: No future reminder set
Green: The Lead has been actioned and has a future touchpoint scheduled