Coincidencing

Editing is going smoothly, and in trying to reorganize scenes and make connections between characters, I've come across things that rely on coincidence.

In my story this doesn't happen as often, as my setting is in the first volume limited to three small kingdoms, and it has a lot of everyone's-related-to-everyone-else happening, especially among the upper classes. However, I've come to ask myself- what is taking coincidence too far in a story?

In life there are crazy coincidences. For instance, my brother and I visiting family months after our grandfather died and going to a 'paint your own pottery' place only to meet a woman whose own grandfather died on the same day as ours, across the street from our grandparents' house.

If this turn of events happened in a book, would you find it believable? At what point is coincidence too much?

The general consensus seems to be that coincidence becomes unbelievable when it becomes too convenient to the characters or the plot- once it becomes a deus ex machina.

A general rule also seems to be that if something makes things worse for your characters/protag, you're doing it right. However I'm sure it's possible to overdo that as well.

A good example of this would be Les Mis, where coincidences (as with most things in Les Mis, to be honest) are usually unfortunate for Jean Valjean. Victor Hugo also, as I have been informed over-enthusiastically by two friends in the room with me right now, plays a lot with coincidence purely because he can.

I feel like it also can make a world more real, to have random coincidences, because these things do happen in real life. To make a random character related through some convoluted tale and happenstance event, or have that apple fall on the old alchemist's head. It makes a world just as messy and intertwined as ours, just like having a character trip or stutter over their words makes them more relatable and susceptible to gravity.

I'm carrying on, in the meantime, and adding more connections and subplots- most of which revolve around family members and their hidden mischief.