What is your USP (unique selling point) and is your initial call to action strong enough to grab their attention in the first 3 to 7 seconds ? If not, you might want to think about a redesign.
We have 4 seasons, so that means at least 4 flyers. Then you've got pre and post each season so you've now got 8 flyers. Add in 4 more and you can send out a different one each month.
Flex your offers. I see the same flyers come through my door month after month and they go straight onto the recycling pile. Change the offer, change the colour and I might read it. Spend some money on decent paper (min 300 gsm) and I'll think you're more serious than the 130 gsm cheapo flyer in two tone.
Don't analyse your own industry. Get someone who knows nothing about your business to give you some critical appraisal.
Out of 1000 sent, I'd expect between 10 to 20 calls, around 5 to 10 appointments and half that number of ongoing sales. However, this is on the back of regular drops. If they see it is your first drop, then they don't have the same confidence.