Many students make me this question and this is hard to answer without demotivating anyone.
In the process of mastering a musical instrument, it all depends on our expectations and objectives. As an example, ir you want to play as a professional you should do as many hours as a professional, that is to say 8 or 10 hours a day.
When I started I used to stay all day in a room playing the guitar and I only left it to eat.
To master an instrument is very demanding and it requires a lot of dedication and perseverance.
This is only applicable to those who want to play as well as a professional, not to those who aim to get by.
Study hours for an amateur:
For an enthusiast who aims to master the guitar at an intermediate level it is very importan to follow these recommendations:
-It is important to spend at least an hour a day and it is more convenient if it is always at the same time.
-To structure the syllabus we need to study (This is really important. If we do not do it like this, we will just beat abou the bush and the time will have gone by without having done anything)
-To review every day in the beginning everything we have learnt. This is very important in order to remember all the contents, move forward and not backward.
-To use all the resources offered with our P.E.M.I. method, whether you work on a phrase or you take advantage of the unconcious state. We explain all this in the book The Vademecum of the Flamenco Guitarist (Original title: El Vademécum del Guitarrista Flamenco)
-To set short and long term objectives (It is important to set realistic goals)
-To work more thoroughly on the part we can not play well. If we only have a mistake in a specific part we should focus on that and not waste our time practising the part we can play well).
-To work very slowly and with the help of a metronome, as well as using your foot to mark the measure all the time (THIS IS THE MOST IMPORTANT OF ALL)
These are the recommendations I give to all my students, since I have seen they have worked in many cases.