If you're going to use a Faraday bag, use it regularly, like every day at random times.

Imagine you are being accused of a crime. The crime occured at 8pm. The phone records show that your phone went dark at your house 7pm and then reconnected at 9pm at your house. The crime scene is 1 hour away from your home by foot. Records show this is the only time your phone went dark in a very long time.

So if you bag your phone (aluminium foil bags work pretty good too), do it regularly, randomly, and don't bag it and unbag it immediately before leaving or after getting home