On the quest for maximum cold storage life with minimal expenditure, I've taken a twofold approach.
First off, I studied and studied, and studied on coolers. Oddly, the SECOND longest ice retention cooler in a national test, and supported by various reviews, YouTube videos, etc. Was the lowly Lifetime cooler, specifically the 77 qt model priced at $147 with free shipping at WalMart. Oddly, I couldn't find it in any of several stores, but now when I go for the link, it's in my store.
https://www.walmart.com/ip/Lifetime-77-Quart-High-Performance-Cooler/775870674But wait! There's more! I want the world record ice retention here, because... why not?
A lot of people line their coolers with Reflectix, but I didn't like that idea - the water gets all in it (and I tend to forget to dry out coolers in a timely manner), it takes up space... I thought "Why not make a cover for it - a cooler blanket? This would have the added bonus of reflecting sunlight before it ever heated the cooler!
Home Depot doesn't carry Reflectix in store locally, but they have their own brand. If you're doing this exact cooler, this took two rolls of this and a little over a roll of tape.
https://www.homedepot.com/p/Everbilt-24-in-x-10-ft-Double-Reflective-Insulation-ADD04-610x3-048/307281313Here's the tape
https://www.homedepot.com/p/Everbilt-Reflective-Foil-Tape-TAPE-50MM-x-10M/307281314Started by wrapping the cooler as tightly as I could (figured it would loosen up as I worked a bit, and it did), and cut off the excess. Taped the outside seam, slipped it off, taped the inside seam, put it back on and put the scrap piece on top.
Then just wrapped it up like a Christmas present
Second layer same as the first, except I put the seam on the back of the cooler opposite the first layer seam on the front of the cooler. When I laid the scrap piece on top, I taped it down to the first layer so the first and second layers would have a mechanical connection.
Then slipped it off. Pretty perfect fit. I'm done except I started to run out of tape, so I only tacked the two layers together on the bottom. I'll grab another roll and finish up to have it all smoothed out. Also had to tack in the little top piece from inside.
Whole thing took probably less than 30 minutes, and the better part of half of that was fighting the tape. When you take it off the roll, it immediately wants to curl back on you. As happens, I found the solution completely by accident. Forget the roll. Let it all fall off the roll, stick down one end, and peel away as you go. Of course as also happens, I learned this about three strips from the end.
So now I have $175 in it. Let's see how it holds up against the big money!