Change of content on an AdSense page

[Bubzeebub]

If I have a page with AdSense ads on there and revise that page every day, why doesn't the AdSense ads change? Shouldn't the ads change with the content on the page? If I put an ad about apples I should see apple ads. If I put an ad about oranges I should see orange ads. Am I wrong in thinking this?

[Jenstar]

The AdSense bot does not visit the page on a regular basis like the regular Googlebot. You can change the ad unit size to trigger a revisit, otherwise it can be weeks before mediabot comes back to check the page.

[Bubzeebub]

Change the ad unit size to trigger a revisit? How so?