There are many opinions about diaper washing, and many people have developed additional steps and routines based on their individual needs. Our advice is to start simple and adjust only if necessary for your baby or water-type.
Some babies require fragrance-free or enzyme-free detergents; most don't.
Drying cotton diapers in a dryer, even on high heat, is perfectly okay although an occasional sunning of clean, wet diapers will go a long way to freshen them and reduce or eliminate staining.
With any diaper items, it's important is not to overload the dryer as its lint trap may get stuck. Overheating in the dryer can melt the urethane coating on the PUL of your covers and AIO's.
If you choose to sun the diapers or line dry rather than use a dryer, we strongly suggest either laying the diapers flat to dry, or hanging them horizontally rather than by the waist or front section. Hanging wet diapers by the waist allows the heavy, wet weight to pull on leg elastic, which may reduce its useful life.
How many diapers to wash at a time depends on your washer, your washing routine, your philosophy, and your diapers. As a general rule of thumb, wash no more than 18 fitted diapers or 24 prefolds at a time. You may be able to do more or less, so do a little experimenting to find what works best for you and your washer.
Like towels and tee-shirts, diapers become more absorbent over time. This is especially true for cotton fleece and unbleached fabrics, which requires some initial "roughing up" in the washing machine.
Most detergents suggest using an obscene amount of detergent. Use enough to clean, but not so much that it leaves residue. If you see suds during a second rinse or a wash with no detergent, you're using too much detergent. Detergent residue attracts and retains soil and odor. It's best to always measure the detergent instead of eye balling it.