Toaster shopping is simple compared to most kitchen appliances, but slot dimensions and the shade dial's real behavior are worth understanding before assuming any toaster fits any bread.
Slot width and depth matter more than slot count
A toaster with wide, deep slots accommodates thick artisan bread, bagels, and toaster waffles that narrow, shallow slots simply can't fit properly — a genuine practical limitation, not a minor inconvenience. Slot count (two vs. four) mainly affects how many pieces toast at once, useful for a larger household, but doesn't help if the slots themselves are too narrow for the bread actually being toasted.
The shade dial is relative, not an absolute measurement
A toaster's shade or darkness setting controls toasting time, not a precise, standardized darkness level — the same numbered setting can produce different results depending on the type and thickness of bread, how many slices are toasting at once, and even how recently the toaster was last used (a still-warm toaster from back-to-back use toasts faster at the same setting than a cold one). This is why finding "the right setting" is often a matter of experimenting with your specific toaster and typical bread, not simply picking a number and expecting consistent results across every use case.
A bagel setting genuinely does something different
A dedicated bagel setting typically toasts only one side of the slot at full heat while using reduced heat on the other side, appropriate for toasting just the cut side of a bagel while gently warming the outer crust rather than fully toasting it. Using the regular setting on a bagel toasts both sides fully, which can over-crisp or burn the outer crust while the cut side is still reaching the desired doneness.
The one thing people forget
Unplug and clean out the crumb tray regularly — accumulated crumbs are a genuine fire risk in a toaster, since they can ignite from the heating elements' proximity, and a toaster's actual performance and even heat distribution can also degrade over time as crumb buildup interferes with airflow and heating consistency inside the unit.