Lindsay4 said it's all about balance. I couldn't agree more, if you get the balance right then the garden will look after itself. However using chemicals to kill bugs destroys the balance. Don't think I'm judging you, but because what does it matter what I think? I personally have found that I don't have any greenfly on my roses, I don't have any, that I notice at least, leaves eaten by slugs. I don't even see big slugs, I find the odd little tiny slug in the grass but I certainly don't see those 4 inch long ones that I see on a night across the road anywhere in my garden. I have so many birds, including masses of sparrows, and more kind of Tits that I can name that I don't have a problem with bugs. If you spray chemicals there will be collateral damage, that is the poisoned bugs will be eaten by frogs, hedgehogs, hoverflies, ladybird, garden birds , etc., and will inevitably succumb. We have dwindling numbers of so many of our birds, sparrows were once so common. If you can look yourself in the mirror in the morning knowing you've contributed to the demise of our British wildlife then so be it. But when you cry about judgement I think it's your own judgement that you're concerned about.
Anyway. Balance. Yes git it right but remember using chemicals WILL upset that balance. AND they persists.
When I moved in I did feel I had to resort to Roundup for couch grass and Astrantias which were everywhere. But I found I couldn't justify it when I saw my dogs eating grass that may have received a bit of wind blown weedkiller and when I thought that bit of couch could have been eaten by a caterpillar which was then fed to a wild bird's chick, I had to say enough! It was me who was the judge me who I had to look in the eye in the morning, me who had to live with potentially harming some other living creature. So, no, NOTHING, I put in my garden is worth that. No plant I buy is worth me not being able to live with myself! And I love my garden. I love my plants. I've got an HND in horticulture, I've sent my life in Horticulture. Don't think becaseu I don't 'protect' the plant I don't love it. I just have a bit of perspective. My garden isn't in a glass bubble on a shelf in a museum, it's part of the world and I have a responsibility to that world. A plant is a plant, it's food for something. Deny that and you've got a big fight on your hands. I prefer to be happy, I don't wont to live my life as Captain Ahab thanks.
Well, I didn't mean to go on like that. Happy Gardening.