There is research into this - your intuition is pretty much in line with best practices (though 7 isn’t magic compared to 5 or anything). Eg http://citeseerx.i

There is research into this - your intuition is pretty much in line with best practices (though 7 isn’t magic compared to 5 or anything). Eg http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.839.7070&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.839...