My 2c here: Depth gauges are just consuming space and weight nowadays.
Even if your dive computer dies during a dive (something quite rare nowadays) you can rely on your buddy as a reference - you should be heading for your SS anyway at that point (as you also loose your NDL measurements) and in any way you don't need 100% accuracy with depth (contrary to NDL where you need more accuracy especially if you dive on the limits and hence your buddy can't be regarded as a reliable backup due to possible differences in dive profiles).
YMMV
I worked on dive boats through college and dive computers were always the weakest link -- either through flooding; mechanical damage -- especially those with transmitters; that, or sundry battery issues. Since the lion's share of divers are weekend warriors, equipment is seldom maintained or even given much thought, eight or more months out of the year.
Provided that you have a watch and can recall your old NDL tables, there is no reason to abort a dive, when you have analog equipment on hand. I carry both and when a computer went into an anomalous error mode a couple of weeks ago, I simply shrugged it off; checked the bezel on my watch; and continued a second dive -- no big whoop.
Unless your buddy is a conjoined twin, depending upon another diver -- and his or her potential dive profile -- is a liability . . .