Quick slots

By binding a button to +slot1, you can fire slot1 by pressing that button, without having to first switch to that weapon. This can be used for all slots and may be more useful to some classes than other (like medic/engineer melee).

If you use quick slots, you might also want to bind r to reloadnext. This will reload each weapon in your arsenal (though you need to click it once per reload) instead of just reloading your current weapon. Otherwise you might be left with an empty weapon on your quick slot just when you need it.

Using a quick slot will not affect your weapon state (i.e. your current/last weapon).