How to use the online timer
Practice is the one activity where the length is almost always agreed in advance and almost never kept. Half an hour is what teachers ask for and what most people can hold real attention through, and it is also roughly what a flat with neighbours on both sides will tolerate on a weekday evening without anybody saying anything in the lift.
These pages cover practice on the instruments people actually learn at home — piano, guitar, violin, drums — along with singing, which needs a shorter session because the voice tires in a way fingers do not, and a general practice block for anything not listed. Headphones and practice pads have made evening sessions possible in towers where an acoustic instrument would not be, which is why so much of it happens after work here.
The advice is the same across all of them and is duller than anyone would like. Play slowly enough to be accurate, work on the specific bars that are not working rather than the whole piece, use a metronome even when it is uncomfortable, and finish with something you enjoy. Thirty attentive minutes beat two distracted hours, and they are far easier to repeat tomorrow.