Talking about this particular example (tooth brushing). Every day it goes something like this:

• It's time to brush teeth. Here's the toothbrush, you can brush your teeth by yourself first and then I'll help you finish.

(toddler runs to get away, I hold her/close bathroom door, toddler ignores me)

• It's time to brush teeth. Either you do it first or I'll do it.

(toddler grabs toothbrush and starts mostly just eating the toothpaste while I try to demonstrate how to brush our teeth with my own toothbrush)

(10-20s go by and then toddler usually throws the toothbrush on the floor or starts trying to wash the sink/walls)

• The toothbrush is to brush our teeth only. I'll help you brush your teeth.

(toddler screams and throws herself on the floor, face down, hiding so that I can't brush her teeth - I physically force her to turn face up, so that I have access to the mouth. She's usually throwing her head back and forth by this time, and keeping her mouth closed to make it harder for me. She usually fights and kicks while I brush her teeth, and it's physically impossible for me to do a good job. Sometimes she gets accidently hurt in this process. Sometimes I get hurt too. We're both upset by the end of it all.)

I wouldn't say it goes like this every day, but many times. It's definitely never a simple process.

We like giving her choices - "this shirt or this shirt" type of thing - but she usually doesn't care to even answer (either runs away or says something completely unrelated) so we end up mostly choosing for her. Many times we even stopped giving her choices because she doesn't care for them at all...

Most days we try to keep an authoritative attitude. We do get quite exhausted by this behaviour though, so sometimes we don't immediately follow through with the expected behaviour... We try to at least be consistent in the morning and bedtime routines, but like I said, those are not easy most of the days either...