mrkgnao: How often do you update your database? Is it at fixed times?
Are you seeing outdated content? I'd be interested in what specifically, if so...
To answer the actual question: It differs a lot based on content. Simplifying a bit:
- For prices, I check for sales 3x/hour, and do a full price-check for all products if that sales-check indicates one is happening, and otherwise 3x/day during the Polish day, also updating non-US prices for all products where the US price changed (staggered per country if I'm reaching stated API limits). Besides this, I do a full price-check for one non-US country/weekday, and if I see any changes there, I update the same products for all other countries.
- For basic product details, I check 4x/day during the Polish day, with an additional check if a price-check indicated that a product disappeared, and sometimes I bump up the next scheduled run if I happen to manually spot a new release (have a todo list item to automate that by checking the news API which eiii pointed out, after which I can probably reduce the scheduled frequency to 2x/day).
- For extended product details, I check each product a bit more often than 1x/week (basically doing lots of small batches spread out over time, with a total running time of ~6.5 days), plus for specific products whenever the basic details get updated.
- For bans, I check whenever I detect a new product.
For all of this, there are some fixed times at which the first run triggers, but all the conditionals add so much variance during the day, that effectively there are no fixed times.