I find myself using clamping to eliminate fireflies in my render. If my scene has bright lights with a bunch of reflective surfaces, it's not uncommon to get abnormally bright pixel artifacts (referred to as "fireflies"). Clamping is great for eliminating those high registers of light energy.
Denoising I'm using a lot lately. It allows us to use significantly less samples which saves a ton of render time. It's especially useful for still renders. It can look odd and splotchy with animation.