If you have epilepsy, do you ever NOT take your medicines?

[Gameboy]

My SIL was diagnosed with epilepsy a few years back. She tried quite a few different tablets, but now seems to be on one which is quite good for her (i.e. she doesn't have seizures very often)

But she told me today that she doesn't always take her tablets, which I (as a non-epilepsy sufferer) found really strange?

Is this normal? Why would you not take something that helps you?

I didn't like to pry, but my initial reaction was to think that she's being a bit careless?

Not a good idea, as it will take a little while to get back up to therapeutic levels. If she has a break through seizure she will be without a car for (IIRC) 3 years, or a year if she only has seizures at night.

Big thing to risk