How long are Meliora Cleaning Products shelf-stable? The short answer: It depends. How helpful is that? It depends. The long answer, and the one you’re probably looking for here, is:
For Our All-Purpose Cleaner
When we talk about shelf-stability for our All-Purpose Cleaner, we’re referring to it mostly in the liquid state - after the cleaner has been mixed with water to create a liquid solution. Any time you add water to something, you have to consider microbes that could develop and cause bacterial/mold problems within the product. 
We don't use a preservative, so it is important to understand how long the mixed liquid product can last before that microbial growth begins. Our All-Purpose Cleaner has been tested for shelf-stability (time on average in-home "on the shelf" conditions) for six months without microbial buildup. After six months, we recommend dumping the unused product, rinsing out the bottle, and starting with a fresh batch.
In its solid state, the All-Purpose Cleaner is able to last years on your cleaning shelf, like our other products.
For Our Other Products
Everything else we make is either a powder or solid. As a result, pretty much anything else (currently) from Meliora Cleaning Products has an extended (years-long) shelf-life to be usable and effective as a soap or cleaner. We’ve used 4-year-old Laundry Powder and it had the same cleaning power and results as a freshly-made batch.
What About Clumping?
At some point, moisture can enter the powders for our products and cause the ingredients to clump or harden, but they’re still okay to use and fully effective. In those cases, we suggest breaking up the product with a spoon and then measuring the amount needed. Not a fan of the spoon method? Keep those lids on tight between uses.
Also, be sure to switch your Laundry Powder Refills to our reusable canisters or other containers that keep out air and moisture to avoid this clumping.
Will My Scents Last?
For any scented product, including Laundry Powder, Dish Soap, and Bath and Body Soap, the plant-based essential oils we use for scent will fade over time. While older products may not smell as strong, the products still work as intended.