Is there a set precedent on giving gifts to caregivers?

I remember when Mom was a private duty nurse, she would sometimes come home with gifts. I was very young so I don't remember the specifics. But, what are your thoughts and ideas for giving caregivers (hospice staff and private pay) gifts for Christmas or after your loved one passes? I guess the tricky part will be finding where to send the gifts and thank-you notes after Mom passes...