Some ideas regarding companion planting have been around for a long time and, in the same way as many 'old wives' tales', they may contain an element of truth although this may not be scientifically proven.
Allotment growers who surround their carrots with onions are using smell to confuse carrot flies. The same is true when planting French marigolds near to cabbage, trials have shown that their smell will attract cabbage white butterflies away from your brassicas.
The same French marigold has also been shown to reduce the instance of potato eelworms and, along with Nastertiums and Poppies, will attract hoverflies who veraciously control aphids including whitefly infested tomatoes.
Blackfly who would normally attack your runner beans can be also sidetracked by Nasturtiums. Further defence might be provided by Savory, a herb known for its medicinal qualities, that is said to repel the same aphids.
Pollination can be improved by introducing a variety of pollinator friendly plants. Bees will flock to lavender, wallflowers, foxgloves, (marigolds (again!) and borage, with the knock on effect that they'll pay your plants a visit as well.
Growing different types of plant will also make it difficult for some pests that rely on sight to find their intended prey, their favourite plants hidden by other less welcoming ones. Tall plants that provide shade may also help prevent vegetables from bolting.
Sunflower and honeysuckle are two plants that will attract birds who will no doubt turn their attention to unloved and unwanted slugs and snails. Encouraging weeds is problematic, they may play a part in creating a varied and wildlife friendly culture but will also compete for moisture and nutrients with your vegetables.
So, instead of hoeing, why not try planting fast growing crops such as lettuce among slow growing brassicas. This is a system proven to discourage weeds and is a very efficient and productive way of growing vegetables in close proximity.
There's every reason to think that at least some companion planting works and, even if not all is proven, the characteristics of a vibrant mix of plants will undoubtedly form a varied and healthy growing environment.