Daily PrEP is somewhat forgiving with missed doses, which is an advantage it has over condoms, which provide no protection when they are not used. From the write-up of a study on PrEP’s protection:
In terms of stopping PrEP, after 30 days of daily dosing, the estimated protection offered by the PrEP remaining in the body from HIV transmission via anal intercourse was 97% 24 hours after the time of the first missed dose, 96% after three days, 93% after five days, and was still 90% a week later. (Source from AidsMap)
However, studies only demonstrate that level of protection for cis men having anal sex. It