What jpeg quality settings to use?

[Energize]

Once you've finalised editing a photo and want to save a copy to "publish" what jpeg quality setting do you tend to use? I can't tell the difference between 75% and 100% for example.

 

[Energize]

For putting on the web; my website, Facebook, Flickr etc.

I don't foresee all my backup copies being destroyed.

 

[Energize]

I don't mean storing for archival purposes, I just mean a temporary lossy copy for quickly uploading to the internet, at 100% they'd be much slower to upload.

 

[Energize]

Ok, thanks.

If I have images that I want to archive at a low resolution due to quality, do I need to downscale after cropping and then sharpen, or can I just sharpen them at the zoom level the image will be downscaled to, then export?