The saying often quoted is "Don't go faster than your smallest bubbles."
If a diver is properly equipped with a depth gauge and timing device, then it is not something they would ever need to use. At best, it is a last resort option for instances of equipment failure, where you don't have a working depth gauge with which to judge your ascent speed . You can, of course, conduct a 'count' to replace your timing device for ascents within recreational ranged.
Even if your depth gauge and timer failed, you should still be aware (situational awareness and/or adherance to your dive plan) of the maximum depth you had attained on the dive. Thus, you could still conduct an ascent using a mental timing count - assuming the deepest depth. Any over-estimation of depth, or slower than accurate count, would only serve to provide a slower, more conservative, ascent. Include an extended safety stop into that ascent and you've made yourself pretty safe.
And, of course, you have a buddy who also has a working timer and depth gauge (or computer) who can assist you to the surface. (If no buddy, then you are properly equipped with redundant gauges for solo diving, yes?)
Or... you might have a DSMB that you can deploy on ascent - where you have marked out/knotted regular or critical depths along the line. You can then use this to maintain a controlled ascent rate..
Which leaves 'following your bubbles' extremely low on your list of contingency options for ascent in the event of a critical gauge malfunction.
You won't get taught this method on any official training course, as it is an inaccurate and non-foolproof method exposing greater risk of error leading to DCS.... thus not official sanctioned by any of the main training agencies.
