I scan my yard almost every day. Sometimes several times a day because I enjoy it. They say 10 minutes a day is better than 70 minutes in one session because you can get to problems before they get too big.

I like shredded leaf mulches because they are free and fallen leaves don't stand out.

I use a dandelion digger or a shovel for large weeds. I disturb the soil as little as possible so not to stir up more weed seeds.

A good mulch can help with unwanted plant (weed) growth.
How often to "weed" depends on many things and no one can tell you how often you need to "weed". Some people are out every day while others find once a week or two works for them.
The best tool for removing "weeds" is your fingers. If you need a tool of some kind you have waited too long to remove the "weed".

It sounds silly but the answer to 'how often' is 'as often as possible'. As kimmsr says, regular patrolling and removing the odd seedling as soon as you spot it will save a lot of time and effort in the long run. Weeding is an integral part of gardening and some of us quite enjoy it. It is very relaxing just sitting or kneeling in the garden weeding and musing. It is also a way of getting to know your plants intimately and recognise them in all the growth stages. Anyone who weeds regularly soon stops pulling up desirables by mistake. Weeding is also an opportunity to spot pests before they become a problem.

I hate weeding too. Letting weeds grow until you have "weeding to do" is just plain mean to yourself - be nicer! While you're enjoying your yard and flowers, pluck weed sprouts as they are spotted.