Getting started
Can I use odo on two phones?
Yes
Sign in to the same account on both. Each phone records the drives it is on, and they all land in one log.
Both in the car
When both phones record the same drive, odo keeps one and sets the other aside, so it is not counted twice.
Finding a phone
Settings → Devices in the web account lists every phone signed in, and Locate asks one of them where it is. It answers when it is on and has a moment of signal; the answer is kept for 30 days. More in Can odo find my phone?.
Pausing
A pause belongs to the account, not the phone: pausing on one pauses both.