What I said about the multi only applies to my DIY formula. Plenty other recipes (as well as the official Soylent) use vitamin powder mixed into the soylent, which would potentially degrade.
If you’re going the DIY route, there’s plenty of websites with decent bulk food prices that you can purchase from online. Since I mix a weeks worth of powder at once (about 1 1/2 cups of mix per day), bake batches in bulk (about 3 days worth) and store it dry, there’s plenty of time savings to be had. I’m currently munching on a spicy/garlicy soylent, a cherry cake soylent, and a mild, neutral flavored soylent that I’m combining with pumpkin cream cheese (yum!).
Knowing my own eating habits has helped me tailor soylent to them, rather than the other way around. I incorporate caloric overhead (and reduced sugar in the mix) for snacking, but I still get all the nutrients I need from the single multi + my daily intake.
When I anticipate having Simple Food meals, I cut back on the amount of soylent I eat to compensate. Yesterday, there was a communal breakfast that had bagels, tuna, salmon, etc. I ended up eating half a days soylent at work and saved 1/4 of a day for dinner. This has actually been happening almost all week (wedding, family dinner, etc.) Even with all this excess consumption, I’ve still been losing weight without feeling hungry or deprived in the slightest.