If it's humanly possible quote shipping charges to ALL destinations.
Bernie's comments are right on, over the years many people (mostly buyers) have commented that unless they are desperate for a particular item they simply will not consider purchasing an item if the shipping is not indicated.
Reasons given...
- Can't be bothered
- tired of not getting a timely reply (or any reply)
- experience that sellers who don't specify usually charge high shipping (ie: will require Priority Mail for cheap items)
- sellers who don't quote International shipping either aren't really interested in International buyers ir are inexperienced
You could leave out Canadian shipping amounts if they are difficult to determine but for most of what you sell determining an International shipping rate is just too easy not to do it.
I think you can be certain that for every potential buyer who ask for a shipping quote there will be many more who will simply move on to a different seller.

"What else could I do? I had no trade so I became a peddler" - Lazarus Greenberg 1915
- answering Trolls is voluntary, my policy is not to participate.