It's never too late. When you lose a loved one, you get a flood of sympathy cards and phone calls, and then people move on with their own lives, and you still feel stuck in this moment of grief by yourself. A note a month or two after the loss, or even a year later, can help them not feel like they're the only one grieving the person's passing.

I agree, the sooner the better. However, as we know grieving is a long process and people are healing for a long time after a death. A nice card out of the blue to let them know they're still in your thoughts definitely couldn't hurt.

I think anything that brightens someone's day is a gift.

I don't think it's ever too late to let someone know you're thinking of them, and that you're there for them if they need you. But the sooner, the better.