I always find it lasts several days in the fridge but did not know if there was some rule of thumb related to fluff and freshness.
I have whipped cream a couple hours in advance, cover and refridgerate. I used a wisk to reconstitute if it gets a bit watery.
Even overnite if necessary.
If you take a large marsh mellow and nuc it in the micro for 10 to 15 seconds, you want to watch it puff up and get soft and do it right before you are going to add it, and then add it towards the end of whipping when the cream is getting stiff it will stabilize the whipped cream indefinitely
I think it's best freshly whipped, but if you need to whip it in advance, add some gelatin (that's been rehydrated) to stabilize it. We use gelatin to stabilize items w/ whipped cream in the bakery where I work.
If you use real heavy cream, it can be whipped a day ahead. It holds it's shape nicely if you whip it stiff enough. Just be sure to cover it well and refridgerate. I never add anything, such as flavoring, until right before I use it. You can just lightly fold your flavoring in and it's good to go!