I'm trying to mentally line up roughly where we are in the timeline of TFA and I think I have it about figured out (note: obviously the day lengths of Jakku and Castilon are unlikely to be the same, much less the timezones of Neema & the Colossus so there's bound to be some wiggle room by at least a few hours either way): -
OK, so Poe was captured on Jakku at night, we then got a quick overview of Rey's daily routine, ending with her finding BB-8 just before sundown, meaning BB-8 was out in the desert almost the whole day and maybe most of the previous night. Next we see Rey & BB-8 at Neema in broad daylight followed by Poe's escape with Finn and their crash in the desert (also in broad daylight), followed by Finn walking for presumably several hours, arriving at Neema Outpost at what looks like high noon in the shots of Finn drinking, but either late afternoon or early morning in all the others. Plus it seems likely Rey did some salvage work prior to arriving at Neema (because 1) she needs to eat and 2) we see her trade some before Unkar Plutt tried to buy BB-8) so I'm inclined to go with the latter.
That means by the time Rey & Finn leave on the Falcon it's been almost two full days since the village massacre. From there until the destruction of the Hosnian system everything seems to happen more or less in real time with no significant time cuts, so a few hours at most making it almost exactly two days, perhaps a little more since the movie began.
From there I'd say it's at most another day, maybe as little as 12 hours from Snap's recon flight to Starkiller, "rescuing" Rey and getting everyone (except Han) back to D'Qar. So that's at least three full days, maybe three and a half. Where it gets a little fuzzy is how much time passed between R2 & BB completing the map and Rey leaving. Since both she and Leia appear to completely change costumes, so it's fair to assume that's day four or five.
How long it took the Falcon to make it to Ahch-To and how much time passed between Rey leaving and the First Order dreadnought showing up is also a bit fuzzy, but since Leia changes outfits and hairdo again, I'm thinking at least another day, if not two.
From there on out it's a pretty explicit timeline with the Resistance fleet having 18 hours of fuel left to get to Crait at sub-light, following what can't be more than a day in hyperspace, max. Rey spending at least a day and two nights on Ahch-To (though like Dagobah, time there may be acting weird.) And a few hours at most to cram in everything from Finn, Rose & Rey making it back to the final flight out on the Falcon before the credits roll.
On the Resistance side of things; in 'The Core Problem' Kaz got back to the Colossus after parting ways with Poe (who said he's leaving for Jakku "tomorrow") at night time. The next episode 'The Disappeared' starts in daytime and again ends at night with several characters leaving for Takodana. So that's a full day since Poe left meaning he's either already on Jakku, or already captured at this point. 'Descent' picks up right where the last episode left off and takes it through the night and into broad daylight (it clearly progresses from dawn in the scenes with Doza, Torra & Pyre, to noon-ish with the sinking of the station.)
So as of right now, Poe is still trying to make his way off Jakku, Rey & Finn may have or are just about to run into each other. So we're a few hours away from the destruction of Hosnian system and the attack on Maz's castle where Hype & Aunt Z are still probably located. Note that Leia appears to give Kaz the coordinates of Crait, so she's already planning on evacuating D'Qar, even before Starkiller Base attacks.
TLDR: TFA = 4-5 days, TLJ = 2-3 days. SWR is currently on day 2 of 7/8
But simpler is often best in storytelling. BSG is a great example of this - they happen to have 12 habitable planets in one solar system.
