I'm a newbie on fretless, just acquired an Ibanez SR370EF, lined fretless. I found I could play it out of the box without too many issues. I have very good muscle memory on the fretboard, so I just adjusted my position. I did look at the fret lines much more than I would normally look at a fretted board, normally I only look when making a major shift in position, just to make sure I land at the right position. Therefore my playing on fretless was slower than usual. That's not my issue or my question here. Issue is when I went back to fretted I started hitting bad notes. Playing the fretless kinda messed up my muscle memory. So my question for those of you who have straddled both instruments successfully, is "how do you best spit up your practice so as not to mess up both instruments?" Should I practice on both each day, or should I set a day or two aside and only do the fretless? Which works best?