Do you think it is ok to get a potential maid hire to come on on a Sunday for a trial day?

That's an interesting approach. I guess, everybody would love to familiarise with potential candidates. In the end, you decide who will join your family and live with you. So I completely understand that you would want to have a maid come in and see how she does with the tasks you want her to do. If your maid is already in Singapore and you would transfer her from another family, I would clearly say 'yes, do a trial'. Get her join you for some time, have the kids meet her, and chat with her about her expectations as well. This worked for us perfectly, but we were lucky enough to transfer a maid from friends, who left Singapore. We knew her, we saw her interact with our friends kids and our own son, when we visited. So it was a soft transition for us and we knew who we would hire.