Some quick questions from a railway enthusiast perspective: firstly does the Navigo have journey sector time limits like the Oyster in London does? If I enter the system to simple travel around in the zones and / or wait for a specific train which might be a long time, how long is a tap in valid for? Also... if I am riding trams for "haulage", i.e. getting on a tram one stop then getting off and getting the following tram, is there going to be a problem with repeated tap ins in quick sucession?
If you're talking about Navigo Decouverte, there's no time limit on Navigo journeys as it's an unlimited ride pass for a set duration, most often day or week. It's not a debit-style of pass where you have a prepaid amount of funds which are debited as you make journeys.
If you're talking about Navigo Easy, then the time limit per tap/journey would be two hours on Metro/RER trains and 90 minutes on buses or trams, including transfers. Keep in mind that Metro/RER rides cannot transfer to buses/trams on the same "tap" or ticket. That type of transfer will result in another debit of a ticket. See more about Paris Metro ticket t+ transfers.
Taps after the time limit would debit another pre-loaded ticket from the Navigo Easy.
You can tap on tram, descend, wait and board the next tram & tap it would still be within the transfer time of the original tap and should not debit another ticket.