If you have never had to performance tune your own code, you’re missing out.
There is no greater satisfaction than watching your code run more efficiently and better than it did before.
The best thing about performance tuning is the metrics for measurement are simple – go faster and don’t consume more than what you are already taking.
If you can do those two things, your code is running better than it did before while accomplishing the same task it did before.
You don’t need expensive tools to get the job done but you need an objective and humbling eye to look at what you wrote and say – “what the hell was I thinking when I wrote this” – and not get offended.