I find it a bit confusing the requirements for cleaning chametz. On one hand, your website says that we don't have to go crazy. But then you say that we must make sure there are no crumbs around that could fall into our food. It sounds to me that we do have to go crazy!
The Aish Rabbi Replies
Yes, it is confusing. That's because there are two separate issues at stake.
On one hand, the Torah prohibits the mere possession of chametz during Passover, even if we will not eat it (Exodus 13:7). In Jewish law, any piece of chametz the size of a large olive (50 cc or larger) has to be removed from our possession. Thus, we should clean as much as we can, but not go crazy over tiny crumbs.
The second issue is that the Torah prohibits eating chametz during Passover (Exodus 13:3). What quantity of chametz are we not allowed to eat? Even one tiny crumb!
And that's where the "crazy" cleaning comes in. Because if there are any crumbs around, they could somehow make their way into the food. To prevent that, we very thoroughly clean all areas where we'll be preparing and eating food. This includes washing the kitchen chairs, covering the table, using a different set of pots, dishes and silverware, covering the kitchen counters - and even wiping off the light switches, doorknobs and telephone. We also make sure that our clothes are clean of chametz, in order that crumbs won't fall into our food during Passover.
Areas of the house that you will not be touching during Passover, only need to be checked for the larger olive-sized pieces.
For a more detailed explanation of this issue, see Aish.com's excellent guide to “Pesach Cleaning Made Easy.”
(Source: Maimonides - Laws of Chametz 1:7, 2:13)