It has no serious health risks. You are in control of your contraception. You can put it in at any convenient time before you have sex. It may give you some protection against cervical cancer and some sexually transmitted infections. Putting it in can interrupt sex.
Some people find the spermicide messy.
It can take time to learn how to put a cap in easily and correctly. Cystitis can be a problem for some women who use a diaphragm. Ask the doctor or nurse to check the size of your diaphragm if you suffer from cystitis. The rubber or spermicide can cause an irritation in some women and their partners. Using a different spermicide may help.