I've been collecting videos for years that make me shed tears. I don't easily shed tears if it feels a little too manufactured. Usually what works best for me is just seeing actual genuine unprompted emotion, though sad scenarios without any emotion can do it if the sentimentality is balanced well.

Tried maybe 5-6 videos on the site and none of them worked. :/ Just watched one of my old videos, boom, instant tears.

Don't know about the health implications of crying once a week or anything, but sometimes if I'm feeling a little out of touch with life, watching something sad does help.