Generic Skills vs Specific Skills
Something to be aware of when choosing what to learn and how to learn it, is how general or how specific a particular thing is. If practising something like synth programming, then some things will be particular to a specific synth, some things will be common to a few, and some things will be widely applicable. The more you train widely applicable skills, the more you have already learned when you pick up e.g. a new synth.