Each year one vicious habit rooted out, in time might make the worst man good.

Change works at a pace most people refuse to accept. Pulling out a single bad habit and giving a whole year to it sounds absurdly slow, and that slowness is exactly why it works, since one thing at a time is a load you can actually carry. Ten years of that is a different person. The arithmetic is unglamorous and it is also reliable.

Pick the habit that costs you most and give it the year rather than the week. Do not start a second one alongside it. When you are tempted to overhaul everything at once, notice that the overhaul is usually the thing that collapses by February.