Retimer

Retimer scales an effect's timing as a unit, so the whole thing plays faster or slower while the shape of its curves stays intact. It scales the timing-related properties for each class together.

Using it

Select the transformed effects to retime.
Open Tools → Retimer.
Set the time factor. Timing channels (lifetimes, durations, rates) scale together across the selection.

When to use it

Slowing an effect down for a dramatic, cinematic feel.
Speeding an effect up so it reads in a fast-paced moment.
Keeping a multi-part effect in sync when you change its overall pace.

Resizer - the size equivalent.
Graph editor - reshape individual curves rather than scaling timing.