Around 80 - 90 per playthrough of one game. Why? Because I can and the game allows it. Is ist really necessary? I suppose not, but what is necessary that there are enough recent saves left in case something goes wrong: accidently picked the wrong answer, dying after a longer period of fighting, an unexpected bug or glitch or simply forgeting something before moving on. I had to learn the hard way that the almighty autosave isn't enough to deal with all situations. Saving manually on different slots sure came in handy during the years quite often. And after retiring a character, I simply delete most of the saves.
Save files are small in size and are easy to create. I don't say all people should create a huge amount of saves as I do, but at least consider a rotating system of at least 5 - 10 hard saves: saving before leaving the Normandy, before starting a main mission, saving before difficult choices, or prolonged fights. And I think this should be naturally with all roll playing games.
Over the years, a significant amount of problems in various other RPG supporting boards (Witcher series, Fallout series, Elder Scrolls, Gothic/Risen/Elex series) would've been solved or never even posted in the first place, if the OPs simply had saved on a regular basis. CDPR introduced three rotating auto save slots with Witcher 3, Piranha Bytes even six rotating slots for Elex as a consequence.
ME1 73 saves, ME2 93, ME3 99 (missed lots of places like Palaven's moon)
