Bandwidth can be a consideration, but many trading platforms are designed to work even with dialup-speed connections and are conservative in their data usage. According to the Traffic Monitor feature on my McAfee AV, I'm currently using an average of 60 kilobytes per minute. I'm connected with a 1.2 megabit/sec DSL line. I'm running IB's TWS with 25 tickers and Ameritrade's Command Center with 40 tickers and 6 real-time charts. That's just 25 megabytes per 7-hour trading day. By comparison, I use 20 megabytes a day during my commute on my 3G iphone, doing web browsing and reading newspaper sites and twitter, and my cellular provider doesn't even blink at that sort of usage.