I did this mental math before, but with the previous generation Conquest. I picked up the grey SPB243 and the previous generation Conquest 39 mm at around the same time. The SPB243 ran +25 SPD and my Conquest to this day runs +3 SPD (1+ year of regular wear). I've demagnetized the SPB243, and nothing changed. It's been gone for months and I don't regret the sale. If you're aiming for a smaller collection, then there's a lot of overlap (in use case) between the two, and I can see the Longines staying. And for the poster above, the SPB241/243 also has 19 mm lugs and it has a bracelet with only 2 micro adjusts.