Adjustment matters first
Espresso grind size changes in tiny steps. A grinder that jumps too far between settings makes dialing in frustrating.
Look for a grinder that lets you make small, repeatable changes. That is more important than a long feature list.
Hopper or single dose?
A hopper is convenient if you use the same beans every day. You fill it and grind on demand.
Single dosing means weighing beans per shot. It keeps coffee fresher and makes switching beans easier, but it adds one extra step.
Retention in plain language
Retention is the coffee that stays inside the grinder after grinding. A little is normal; a lot can make the next shot taste different.
If you like trying different beans, low retention is useful. If you use one daily espresso blend, it matters less.
Match grinder and machine
A compact beginner machine still benefits from a serious grinder. A premium machine without a capable grinder will feel disappointing.
Build the setup as a pair: machine, grinder and workflow together.