I use as little to no chemicals in my own garden as possible and always encourage others to do the same. I think everyone needs a little patience and trust that the garden will find its own balance and start to look after itself. Once the garden has established, and there is a habitat for insects and other wildlife the little eco-system that exists in your back garden will sort usually sort itself out without any interference from us or any nasty chemicals.
Many ladybirds are predatory, and they will happily spend their time feeding on aphids and scale insects and can help keep these insects under control. Other species of ladybird will also feed on mildews with only a few that feed on plants but none cause serious problems in gardens.
It pleases us more than anything that we share our garden with the birds, bees and all the bugs in between, and it is their garden as much as ours.