I live in a "good" area but woke up in 2009 to find my garage door wrecked and all my bikes gone, despite door thru frame bolts, chemical anchor bolts securing in the ground anchors and them all being chained together, plus, with assorted motorcycle U locks. Tbh I don't know what else I could have (realistically) done, they must have made right racket and spent a lot of time in there.................
Since then I've not bothered using any security apart from the below cheap battery operated LED lights. I have 2 drilled into the front door and 2 at the back window, total cost was sub £10 and I use rechargeable batteries. I've not had a problem since, but my neighbours have, I do believe the buggers assume a whizz bang security system is fitted and just move on to another shed/garage. It was right palaver getting bikes out for ride before too, unchaining and unlocking stuff..............