I find the crucial time for weeding is early, right after you have planted and your seeds have yet to sprout, or when your seedlings are still quite small. Generally at that point in the season you are watering daily in order to germinate the seeds (and checking frequently to see if anything has sprouted!). It is good to spend 15 minutes pulling out weeds, while they are small and have yet to develop a strong root system. Of course you need to continue weeding throughout the growing season... or do you?
Some gardeners will let the weeds grow tall, harvest the crop, and turn the weeds under. This can be good for your garden too. The weeds will help the topsoil from eroding, and when they get turned under they will decompose and will provide nutrients for the soil. I will caution you, however, if you are planning on adopting the low maintenance style, then ensure your seeds germinate and become established before you let the weeds grow up and steal the nutrients and block the sunlight from your veggies or other plants.
What are your experiences with weeds and weeding?