I struggled with this one, with Mil initially getting really angry each time I tried to introduce the idea of her wearing them - for bed only, at first. I had weeks and weeks of wet bedding to deal with, as she refused so firmly. In the end, at the end of a weeks respite, a carer managed to get her to wear them for just the last night, and the following night I didn't ask her or refer to them, just simply handed them to her to put on - and she did. We had weeks of her removing them during the night on a regular basis, then she started with a lot of day time 'accidents' and I made the decision she should wear them all the time, for her own sake - she would get so horribly embarressed at accidents during the day (though she continued to insist that at night the bed got wet because she 'sweats a lot'
). At first, she was really indignant and a couple of times she changed into ordinary pants. I then removed all her 'ordinary pants' from her room, and since then she has more or less accepted them. If she does object, I tell her its 'just while you're getting over that infection - you don't want your clothes to get wet, do you?' - although she hasn't had any infection for ages, she mostly accepts that, thankfully, and she has pretty much stopped removing them during the night too.
Worth asking the continence nurse for some samples to try, and I discovered last week that the high absorbancy home brand from a certain supermarket (starting with 'S') is actually just as good as the more expensive brands - at £6 for 10, opposed to £14 for 12, if you have to pay for any, it could be worth trying those