A matter of personal opinion and the final discount percent might depend on your customer history, previous purchases etc. I, personally, if it's not a waitlist item will be satisfied at 10% and happy at 15%.
You can always ask politely for a deal sweetener (i.e. extra strap and/or buckle).
I think it depends on the watch you're after. So there's no regular percentage that can be confirmed. But as has been said, 10 to 15% off are possible on some models normally, if you do it right.
I'm coming from the Rolex forums and this is such a breath of fresh air. Watches at a discount and you can actually touch and feel them and walk out with a new watch the same day! Who would have thought.
I'd shoot for 10-15% off. Anything more I might be ashamed and might just go gray.
What discount percentage should I try and get at my local AD for a new Omega Seamaster chronograph?
The percentage of a discount from RRP can vary.
It depends on how much rent the AD had to pay.
And the outgoings (insurance/power/water).
And his monthly turnover/profit.
And the staff burden (shit staff get shit money, good staff who knows the product are rewarded and kept).
And the affects of a global downturn in most markets.
And the AD experience with low ball offers for their products.
There are many factors contributing to the cost of a watch (dealer to you).
My suggestion is to research your local market place, and then make a fair offer if they are open to negotiation.