When I'm being obsessive I twist a new coil once a week (it's kind of a welcoming-the-weekend ritual). That said, I've got coils in some atties that are >2 months old (dry burning is your friend). I can do that because I wick with cotton - easy to replace without needing a new coil - which I tend to replace every 3-4 days or sooner when I'm just not feeling the vape love from my setup.
YMMV, depending on juice type (PG/VG ratios, amount of sugar, etc.), coil setup, and vape style (e.g., high wattage).
The cool thing is it's all in your control - vape (and maintain) how you like. It's all good.