I've found that it's often best to make something *work* as simply as possible before complicating it to run *better* aka...
Finding the right balance really comes down to experience though and we're all growing a little bit. Luckily, we're in the age of Stack Overflow and the like, so I often find myself asking the Google/SO if doing A, B, or C is slow to see what pother people have discovered. About 75% of the time, I only confirm that it's not something to worry about.
Make it work. If there is a problem, then make it work better. :)