the need for decompression (and the required decompression time) is very much dependent on the duration of the dive (i.e. how much gas is dissolved into your bl

the need for decompression (and the required decompression time) is very much dependent on the duration of the dive (i.e. how much gas is dissolved into your blood depends on how much time your blood was fed gases at higher pressure). If your dive is just a quick down,drop some stuff, and back up right away (especially with a gas mixture optimized for depth)… then yeah, you might be able to do it without decompression… …whereas if you stay an hour or two down there, giving a long enough time for the gases to reach their high pressure solubility levels, you better not get back up without decompression.