I guess am well through putting together my basic beginning skill set at the moment, but there's still work to be done particularly with the basic tongue articulations.
Being a pretty single-minded and patient type of chap, it's quite common for me just to work on one particular stumbling block all day (after a warm-up) and if I'm not careful that can spread out to a week or so. Eventually some of the bits I'm not practising (such as keeping above stave open) start going south.
I guess Rowuk will say that I'm not being diligent in setting a structured practice schedule and he'd probably be right.
But a useful little palliative I've found is to dig out a not-too-difficult performance piece that exercises most of the skill spectrum. At first I'll be all over the place with it as it taxes aspects I've not been practising for some time. But eventually it will usually start to turn around after a while.
I know I tend to neglect practising pieces. Maybe I get a little dispirited remembering that they seemed 'easy' when I was in my teens.
How do the rest of you balance technical exercises versus 'proper tunes'.