(L&D) Graves, how quickly do they fade?

Greave for a week and move on...If I owned the EP...Not even a week most of the time! The living got to move and groove...From time to time you might be sad...but once in the ground...the living has got to move on.

Edit: They should have added a crematorium to this or mushroom blankets/suits. It would be a nice green option for burials.

I'm not going deeper because a lot of people are hungry....🙃

It is not the graves that are fading but the soul of the deceased. 
You will not get notifications for those in the premade cemeteries.
I believe that you have three days to visit the lot where they died and strengthen the bond with the mortal world if you so choose. Personally I don't bother with those I have just met once or twice. I only interact with those close that I either want to resurrect or play as a ghost.

Thanks both! I'm not intending to keep all ghosts, it's just that there are soooo many popups warning me that spirits are fading, and not all are graves on that played lot or related to the played family either. Because it says only the first name it is often hard to understand where the grave is located, and the reason for my Q is basically that I had no understanding of how urgent it is once that popup shows.

I want to keep some ghosts, but I will never play them as a household member. I always build background history, so I want to keep just a few older that relates to my created history. Maybe I'll keep only one old ghost per family. Maybe it's easier to keep them going if they move to the cemetery lot, because the game spawning "Mourners" might help keeping the ghosts from fading?

Another thing is that I find no way to see how much faded a given spirit is. I assume it is based on the sum of relation levels, somehow, but I do not know if it helps say lighting a candle at the grave every night (on a home lot). No idea whether it must be done by someone with a relation to that ghost.

But basically, it would be nice knowing if "fading spirit" means that the ghost will leave shortly, or if the popup is mostly a reminder. If it all is restricted to 3 days and not relations, I think I should simply let go of all ghosts as I play rotationally mainly focusing on other aspects than ghosts.

I don't know if they changed something but it used to work like this: when someone dies there is a separate interaction in their grave/urn to "strengthen the bond" or something like that. After the interaction the ghost stays present 90 sim days if I remember right. In the end of that timer you get the notification of them fading away and you have to make the strengthening interaction again. Not sure how many days there is time to do it though. 

I'm not sure if the timer is same 90 days when the grave is on a community lot and if you get the notification.