I wouldnt buy more than 3 months worth like you said. You risk losing the 50 bucks IF they sneak in a firmware check and ban your gamertag AND console from live, just like they did with the xbox1 after the modchip detection came out with a live update.
If your console gets banned from live you can only get updates from latest game discs and burnt to disc from microsofts site. But youll have to get a Core or use a friends console to play on live and download new content.
I would give MS about 3 to 6 weeks to come out with an update that starts detecting and banning all known firmware hacks.
007 has all the gadgets. Batman has a utility belt! 007 drives a fancy car. Batman has the Batmobile! 007 gets all the ladies. Batman has ROBIN!!!