After you spray weeds with weed killer the weeds should begin wilting and dying off within 8 to 24 hours of spraying the weeds.
Some weeds may take as long as a full week which is 7 days for the weeds to fully die off after spraying them.
The stronger the weed killer the sooner and faster the weeds will usually die.
Whenever I've sprayed roundup weed killer on my weeds the weeds would start dying within 8 hours of spraying them and within a few days the weeds would be fully dead.
If possible cut the weeds down and then spray the area with weed killer and weed prevention weed killer every 6 months or at least before spring.
Vinegar and salt as well as dawn dish soap will kill weeds as well but it will take a bit longer than regular weed killer to kill the weeds.
Even with the vinegar and dish soap and salt solution the weeds should fully die off within a week at most.