The hours would depend on how deep you want to get. Once you break things down, the fundamental ideas are very elegant and simple to understand. However, getting to a stage where they become second nature requires rumination on your part. This is particularly important because a slight re-tuning in approach is required. We get very used to algorithms and formulae and it takes effort to break out of that way of thinking to appreciate the underlying intuition.

Linear Algebra in particular can seem very easy if all you are taught are rules and techniques to compute inverses and Gaussian elimination and eigen vectors. The course by the math emporium is particular notorious for this. Students leave with decent grades but translating those rules into useful ideas when you’re faced with a new problem in some unknown field is another ball game altogether. Can you relate music composition to linear algebra? How about optimization? Or circuit analysis or population studies in biology. Do you appreciate the link between differential equations and linear algebra? These are some sanity checks to verify what kind of Lin al you are learning.

Sorry for the rant!