2 to 4 hours a day everyday for the past 10 years seems a bit excessive but it depends on their situation. The most important thing to see would be has this person been neglecting their responsibilities in doing so? Also, another thing i would see is when are they doing this. If they’re at home all day and they do it at a time when they’re alone or they don’t have any other things to do then I wouldn’t mind. If they’re spending all their time in these things, not spending time with the family etc. when they’re at home, then I would not look at that favorably.
Otherwise I’d say 1-2 hours in a day is reasonable for this type of thing.