I claim an extra hour per day on top of my usual operating hours. When I added the extra time up and averaged it out, it's probably more like 1.5-2 hrs a day, when I look at time spent on the weekends/before daycare opens/ and after daycare closes. I didn't want to raise any red flags with CRA, so I just added 1 hour. Think of the time spent advertising/emails/making contracts/creating websites/cleaning the house/dishes/laundry/shopping/banking/meal prep/craft prep/interviews/weekly bookkeeping of receipts etc/repairing damaged items/your house etc.
I have always used an accountant, and never once did she let me know I could claim the extra time. I found the info. last year on this site, and asked her about it, and she said that was fine.
It would have been nice to know sooner!