Portra 400 - Latent Image Stability

I'd like to shoot some Portra 400 and process it myself, but, since I don't shoot color all that often I'd like to hold exposed rolls until I have enough to make a sensible run on my Jobo. If I keep the exposed rolls in a refrigerator or freezer (is either one preferred?), does anyone have an idea how long the latent images will last in top shape? That is, if I process x weeks/months later, what's the timeframe whereby these images will appear as if I processed the next day?

Thanks!

When I am waiting to collect enough C-41 rolls, I too put the rolls in ZipLok bags in the refrigerator.

In the datasheet, Kodak recommends 13C for long term storage of unexposed film. I see no reason to use a different temperature for exposed and undeveloped film.
They also recommend as follows:
Process film as soon as possible after exposure. Protect
negatives from strong light, and store them in a cool, dry
place. For long-term storage, keep negatives at a
temperature between 2°C (35°F) and 13°C (55°F) and at a
relative humidity between 30 and 35 percent.
As for your main question, I expect that Latent Image deterioration will not result in a linear change. But I think that you would need someone who shoots high volumes and has to store exposed film for varying lengths of time in order to get an informed answer. That isn't me.

Thank you both for your input. I have a small refrigerator that runs at about 50 - 55 degrees that I use for various photo supplies. I think I'll toss the exposed rolls in there in a ziplock bag until I have enough to make it reasonable to process and toss the chemistry. I'll probably start with the Cinestill C-41 kit and go from there.

I always batch up color film processing either if sending out (single parcel for shipping) or developing (use one kit). Last year I had Portra 400 120 exposed and undeveloped for 9-10 months and looked fine with the bonus of some Xray during travel.
By the time there was the imprinting issue, I noticed that from the same batch, rolls that were exposed and left around my desk for a month or two exhibited faint imprinting whereas the refrigerated ones did not.
However I have no scientific way to measure the difference, and I can imagine there is.
Perhaps a very slight shift/fog in shadows but my Portra is now expired although always kept frozen.

I am just scanning in some Portra 800 right now that I took 11 exposures on in November, and one picture taken a month ago on it. There is no discernible problem with the "old" exposures. The rolls were stored in a drawer at room temp.