From Tang in the toilet to 101 Uses for White Vinegar, books, articles, and posts on "making your own cleaning supplies" abound. There is a perception that homemade cleaners are the most economical, safest, and simplest methods of cleaning your home.
In comparison to products readily available through grocery and department stores that assumption is often correct on all three counts. What most homemakers don't realize is that 2 industrial products are available that are cheaper and gentler than even homemade solutions. They're also far simpler, because you are only storing and using 2 cleaners for all of your household needs. Our local paper supply delivers to our doorstep for free, so I don't even have to make a special trip!
Homemade cleaners are too acidic/abrasive for regular use on hard surfaces.
Virtually every home cleaner relies on an acidic or abrasive ingredient to break down dirt & greasy residue. The problem lies in the fact that even consumable acids like lemon juice or vinegar will etch and degrade hard surfaces over time. Some cleaners include a shot of dishwashing liquid or a dollop of baking soda which will adjust the pH somewhat, but unless you're willing to use test papers every time you mix up a batch, you're probably etching.
By contrast, industrial cleaners have been thoroughly tested for daily use and every bottle will have an identical (safe) pH when mixed as directed.
Homemade cleaners are harsh for sensitive skin.
We both have extremely sensitive skin, and even washing our hands can be painful in the wintertime. Typical homemade cleaners are outside the normal pH range for human skin, and require the use of gloves.
Homemade cleaners rely on physical action and must be rinsed off.
Industrial cleaners work chemically to break down and neutralize dirt and grease and can be simply wiped off. Homemade cleaners require physical action and have to be rinsed. If you just "spray & wipe" you are potentially leaving behind a film of an acidic/caustic ingredient that will continue to break down the finish on the surface.
Homemade cleaners rely on physical action which requires (drumroll, please) physical action.
Using commercial or industrial products allows you to spray or flood the dirty surface, let it stand for 2-3 minutes, and then wipe away the crud. The cleaner does the work, and does it quickly. Homemade cleaners require scrubbing, scraping, and wiping, all of which are time gobblers and hard on sealed surfaces.
Homemade cleaners require the same amount of product storage as industrial cleaners.
I don't generally keep white vinegar, rubbing alcohol, or ammonia on hand, nor do I have extra boxes of baking soda & borax. Many authors tout the convenience of "ingredients you already have on hand" as a good reason to use homemade cleaners. That may be true for one small spray bottle, but for the amount of cleaner I use regularly in an old house with five people and assorted pets, I use a lot of cleaning fluid.
I typically use plates and cutting boards when handling food, and no one in our house licks windows, doorknobs, toilets, or cabinets.
One of the more compelling reasons to use homemade cleaners is that they are food safe. Because I am not in a stage of life where children are eating directly off a highchair tray or randomly licking windows and doorknobs (don't laugh, you did both as a toddler!), I have the freedom to use chemicals that have been approved for food surfaces by the USDA, but are not technically ingestible. For a family that regularly prepares or eats food directly off a counter, or has children with licking issues, homemade cleaners may be a better option.
The best homemade cleaner is free.
One of the "homemade" cleaners I do use a lot is free: water. Given a microfiber rag or mop cover and hot water, I can clean many of the surfaces in our home without any cleaning product at all. You probably remember your little pink spray bottle and microfiber rag that you used to "help" with cleaning as a little girl.
"Green" simply means it's safe for the environment, not necessarily for humans!
I learned this lesson the hard (and expensive) way. Green cleaners break down into basic non-reactive elements when exposed to water. This means they're safe to go down drains and into septic or sewer system. It doesn't mean that they are necessarily food safe or safe for contact on skin.
There are only two industrial products that take care of our entire home: a non-acidic quarternary cleaner for bathrooms, and an all purpose surfactant for everything else. I use Spartan products NABC (non-acid bathroom cleaner) and SD-20, both of which are economical and work extremely well. Each one is diluted with water to a specific ratio for the job. I buy a gallon bottle of each about once a year. Some hardware or home improvement stores carry the products, but your best bet is a janitorial or paper supply. Ask about delivery, which is usually free. The biggest lesson to learn early on is that "natural" or "homemade" isn't always safer, easier, or more economical for cleaning supplies, beauty products, or nutritional/medical supplements. Take the time to find out!