You can be good at Twitter in about five minutes a day. Spending ten minutes doesn't make you twice as good... in fact, there's probably little measurable improvement. To be great at Twitter might take five hours of daily effort.
At over 48,000 tweets I do not need any more Twitter practice. Lately I've been spending just 30 minutes now-and-then to go through my Twitter Lists and retweet that which I find positive, interesting, creative. Twitter has become such a mire of hate and political bunk that I simply avoid it otherwise. So while Seth's advice is to save time by being happy with being good at Twitter as opposed to being great at Twitter I'm limiting my exposure to it simply for my own well-being.
Side note: the above may lead some to believe I no longer find value in Twitter. I do. Twitter Moments and Trends and Searches are still incredibly valuable. I simply find no value in keeping Twitter open as I used to. Partially due to the fallout from the US political core but also from Twitter's own product decisions to algorithmically castrate its timeline.