It is impossible to post a poll with all the options people would like to have on the topic. This one doesn't give me the one appropriate for me but is certainly stimulating worthwhile discussion.
My normal buddy always has a cheapo little SMB in his BCD pocket. We both always carry them on Boat Dives, drift dives and dives where there is and increased chance they may be needed. Like DrBill diving around home is shore diving in relatively shallow (less than 18M or 60') water. Boat traffic is minimal or restricted, free water ascents from depth or away from shore are incredibly unlikely.
We are more likely to get tangled in fishing line at our sites which means we like to be more streamlined and have less stuff hanging on us. I do need to practice deployment again but our sites are shallow enough that deploying and dragging our very large (6' and 9') vizability devices is pretty impractical. If we deploy we want our SMB's to be vizable from as far away and as high seas as possible so they are LARGE and have reflective patches as well.
We do always carry Whistles, strobe torches, cutting devices and visual signaling devices.