Short answer: As much and for as long as you need in order to do what you wish to do in your music. Every practice session should be a balance of technique and music, and your teacher should prescribe that balance. Also the length of the time spent on anything is far less important than the quality of time spent. For technical work, it's possible that 15 minutes of focused, quality work will do more good than an hour of undisciplined work doing the exact same exercises. For your morning sessions when time is limited, I would probably limit Hanon to no more than a few minutes (5-10), and then move on to other things.
The long answer is that it depends on what you're trying to achieve in your piano playing. If you just want to have fun, and play casually, then just play anything and have fun. There are no rules or definitive guidance in this case, except to simply enjoy what you're doing.
(The below is mostly in response to others suggesting that you shouldn't do any Hanon or that Hanon is a waste of time.)
However, if your goals are more long-term, and wish to advance to the level of playing standard repertoire to the best of your abilities, then the answers are very different. In order to fully express yourself in your playing, you have to have the tools to do so. Things like scales, arpeggios, Hanon, Pischna, Czerny, etc., all serve to give you the tools you need to fully express the pieces you wish to play. These exercises isolate the technical elements found in all music, and learning how to solve these problems will dramatically improve your playing of the actual music. Imagine wishing to paint a vivid and accurate portrait, but being limited to just three colors and one brush. How accurate and life-like will that painting be? Now imagine you had 50 colors at your disposal, and you could mix as many as you want to create just the perfect hue, and you had five brushes of different sizes and material to control each stroke to a granular level? Scales, Hanon, and all of the other technical exercises are your tools, and the more and better tools you have, the better your music will be. If you skip this tools-building phase, then your enjoyment of the music will be far diminished.