How much time does machine learning approximately take to solve certain problems?

Question

Machine learning

Hello.
Sorry for the amateurish question.
The question, of course, is a broad one, however: how much time (approximately) does machine learning take to solve certain problems?
For example, a video was somehow caught in which people who were walking in protective masks were identified and marked on the video. Approximately how long does such training take and on what factors does the duration of training depend? As far as I understand, the machine must process some critical number of objects (learn) in order to begin to identify people moving in masks.
The example was the first one that came to mind. You might as well consider, say, teaching a car to recognize traffic lights or pedestrian crossings, or something else.
Interested in getting a general understanding of the timing (and, preferably, the principles / on the fingers, without unnecessary details /) of machine learning when processing any objects / data.
Thanks for the constructive.

Answer 1

For certain tasks on a particular hardware, using certain algorithms and with certain parameters, training takes one or another time.

Answer 2

It depends on the hardware, on the volume of the training sample and its quality, on the desired accuracy of predictions. Calculated from hours to weeks.

Answer 3

Do not confuse - how long does it take to train an algorithm (or a grid) and how long does it take to study a problem, select and configure an algorithm, select-modify the network architecture, verify the results, and put it into operation.
And then after watching the videos, you might think that training the grid to recognize faces in a mask is a project for two hours or two weeks. The fact that behind this there are years of work of often large teams of highly qualified specialists, the authors of commercials and advertising articles somehow inadvertently omit. And then the messages "how to train the system to recognize faces-voices-emotions-age-nationality-religion-sexual orientation, etc., I do everything according to the article, but it doesn't work for me, what am I doing wrong?" - every third.