Always resize the heads, even on AAs and STSs (and Peters 12 gauge plastic target hulls - really STSs). Resizing is really essential on run of the mill Remington, Federal, Fiocchi and Winchester hulls and Cheddite-made hulls, even more so on high brass versions.
Beware of hulls from guns with especially generous chambers and always check the base wads before loading. Maybe even don't load them at all. You don't need a base wad stuck somewhere in the bore!!
With the light loads we use most, the heads of AAs, STS, and 16 gauge Remington black hulls expand very little in our guns. But, because we shoot them in diverse guns, some with tight chambers, resizing is essential. With normal, low-pressure hunting loads, especially in Federal hulls, resizing is even more essential.