If you read the articles on the internet, a lot will say it's okay. There are posts that will also say that it may be more prone to microbial growth.
Not to mention that depending on how much water you dilute it into, it will become less effective in cutting grease/oil.
There's THAT problem.
So what are we to do?
When dishwashing by hand (or otherwise), here are the steps we suggest.
1) The Preparation
Make sure that you set aside a container where you're going to push any grease/scrap into. You know. Any leftover sauce, oil, whatnot still on your plate, bowl, or utensils. Do the glasses first, then the utensils, then the plates, pots, etc.
You may choose to soak them into warm water, after removing the gunk, and do a pre-rinse. It's not always necessary, but it helps, especially if you have sauces, and you hate seeing your sponge turn a different color, because of it (I'm one of those people).
For used cooking oil or excess grease (like when you fry beef burger patties in a pan), you will need to put that into a separate container, make sure it's already cooled, and throw it in the trash.
Once all the gunk is removed from the plates, utensils, etc, set aside some warm water, and dilute your dishwashing liquid in it.
2) The Actual Wash
Soap the glasses first., move onto the utensils (you can put them back into a glass/cup, while soaping the rest of the dishes), then plates, smallest to largest, then pots and pans.
Why always in the order of glasses>utensils>plates> pots and pans?
Because your glasses are, for the most part only used for water, juices, and the odd thick chocolate or coffee. You always start with the cleanest things, first. Because you're using that same sponge for all of them.
By washing it this way, you're able to dilute your dishwashing liquid and save a bit, as well as put aside any concern you may have about the possibility of microbial growth occurring. The warm water will also help with germ-killing.
We hope this helps!