re: Poker & Trying other variants
I would say it depends on what game your most confident in. I find trying new formats tend to increase your concentration not because it's harder, but because your outside your comfort zone rather than being relaxed. In order to build a bankroll, you must have at least a sizable amount you will respect and pad you from fatal soul crushing variance if you happen to run bad. For tournament poker you need about 60/100 buyins for sngs you need about 40+ buyins and for today's cash games I like to have 70+ buyins , but for most 25-30 will be fine.