Check out the solution in the video TSQL: Quickly Obtain Log Space Used (DBCC SQLPERF). Prevention beats cure, but this is a great command for those situations we haven't had time to look at and need to get information quickly. Also, we see how we can use it to clear metrics, if we need to in our situation. This won't always apply.
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While getting the log space after the fact may be reactive, I understand that there are some environments we're completely new to or run hundreds of servers and may not have had the time to do a quick analysis. If you can, evaluate how logs are set and used before reacting to a situation.
One regular point I like to remind my audience, especially as of recent: we can often solve the same problem with a variety of techniques. While we look at one or two ways to solve the problem, these aren't the only ways we can approach this problem. The most appropriate solution to a problem is one in which you can troubleshoot quickly in the future and one in which you understand. Be careful about applying solutions that solve a problem, but introduce new problems in the future.
A great re-occuring example of this is my discussion on alerting best practices. There are a variety of alerts everywhere for everything in today's development environments, but many of these alerts cause more issues than they solve (one of which is creating a distraction). Be careful about "easy" solutions which introduce bigger problems. Know your environment and where to apply the best solution. Of course, all these being written, it is helpful to learn new techniques to solve problems because they may be useful in the future.
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