When you're developing a database, the pressure is on to get something that works, using an efficient algorithm. When you are getting close to a release candidate, however, there are some programming habits that must be removed from the code, because they can cause unexpected performance problems. In this article, you'll learn how to detect and remove one such problem: reliance on implicit datatype conversions in your queries. We'll use a combination of plan cache queries, extended events, and SQL Monitor.