My dark roots need doing anyway, so it's time for a change.
It's winter, I'm pale. I'm hoping I can pull it off without it aging me horribly.
Now, the worst case scenario I've considered is blue or purple hair ..... I can cope with that 
I've plucked my eye brows, do I look groomed. I've got bleach and I'm off to collect the the toner later.
Anything else I need to consider?