This is always a tough one. Douching used to be used as a cleaning and abortion technique. Both of those are ill guided at best. The vagina cleans itself. While douching will kill sperm it is not 100%. More than that it can cause damage to your vaginal wall and cervix if you do it repeatedly. Back in day Lysol used to marketed as a proper douching agent and well... no just don't do that. Today douching is much more palatable.

Most douching products are not meant for daily or weekly use. They more for when you have something traumatic happen. After your period, yeast infection, or other pH distressing events you can use it to rinse the gunk out. (That sounds so bad.)

Unless a doctor is telling you to douche, there is not really a reason to. Though if you are trying to get pregnant and are wanting a specific gender douching can help. Using homemade douche of 1tbls of baking soda/gal of water will make the vagina more alkaline and sperm friendly. This is good for the weaker male sperm. Douching with with 1tbls of vinegar/gal of water will make the vagina more acidic, this will kill off more male sperm increasing the probability for a female sperm to to reach the egg first. You would need to do this soon before getting it on, otherwise the vagina will begin to go back to normal.

The jist is nay... in general. Consult your doctor and do not use household cleaning products. If you make a mistake and need emergency contraceptive, Google maps can show your where your local Planned Parenthood is. They can help.