One doesn't exclude the other. I wouldn't ever prefer a gauge to a number because of my personal taste — like, I don't know why would one emulate analog clock o

One doesn't exclude the other. I wouldn't ever prefer a gauge to a number because of my personal taste — like, I don't know why would one emulate analog clock on their smart watch, etc. But I still do find gauges useful. For example, I agree that I'd rather have a precise number for HDD space usage indicator. But imagine you have 20 of these on the same screen, and they are not sorted by size for whatever reason. It is not trivial to find min/max/normal, if you don't help the user by providing some simple visual aid, like a gauge, a bar or color-coding. I'm using 20 indicators as an example, because it's more obvious this way, but in reality your vision doesn't work differently if there's only 1 indicator, you just don't understand that, because you still can read "20%" quickly enough, so you think it takes you the same time to process "20%", as it would take to read a gauge (also, you don't care that much how quickly you can read a speedometer, because you kinda already know if you are driving fast or not). But it's not technically true, a gauge really does drive more attention, than a low/high number. (Also, imagine that value oscillates between 68 & 73 — 5 times in a second. You wouldn't care on a gauge, but good luck reading that on a number screen.) So, in most cases when I need to see something really quickly, I would prefer a gauge, supplemented by a precise number.