I've always enjoyed shower shaves! I found that over the sink shaves can be a real challenge. On the subject of de's and cartridge razors, well, I on occasion get nicks with any new blade but fortunately, those nicks are few and far between. I can shave a bit faster with my extreme 3 but the de requires more respect so I let the blade do the work and take my time. One of my favorite de's is 1918 Gillette. Actually, the hardest part is I have to be careful while changing the blade. As for longevity of the blades of either razor, I get about 2 or 3 shaves from each one.
Back when I first had peach-fuzz on my face, nothing other than the de was on the market. In fact, when I enlisted, they gave everyone a Shick de so the disposable razors of today are relatively new to me. I was in my twenties the first time I used one out of curiosity. I remember it was a Gillette something or other. I also tried the Bic razor but didn't like it. I only shaved my face back then but the Bic was too harsh and pulled. They didn't have much else back then but I do remember the injectable razors but never got to try one.