What is the maximum number of sessions I can use at once?
This article explains the concurrent session limit for static residential proxies: they can be used on multiple devices under the same network or the same IP address; DF-IP static residential IPs can be used simultaneously from an unlimited number of IP addresses.
There is no limit on the number of concurrent sessions.
As long as the devices are on the same network (with the same IP address), you can use a single static residential proxy on multiple devices.
Note: DF-IP static residential IPs do not have this restriction. You can use them simultaneously from an unlimited number of IP addresses.