Is there a boundary my laptop has to prevent it from crashing?
Modern processors will slow down or shut the computer down if they start to overheat, to prevent damage.
That's not to say that all consumer-grade low-cost laptops will be able to handle it.
I built a crawler for my own personal use that queries many pages with curl_multi_exec. It uses 98% CPU and memory for 10 seconds on my laptop.
"a program that consumes 100% CPU in pursuit of actually accomplishing something is hardly scorn-worthy; indeed it should be commended for efficiency!" - http://blogs.msdn.com/b/oldnewthing/archive/2010/12/03/10097861.aspx
(Author Raymond Chen is a knowledgable Microsoft employee).
I'm only crawling around a 1000 pages, but I wanted to do more. Is there a boundary my laptop has to prevent it from crashing? Can I crawl a larger number of pages?
The ideal is that it all fits in memory. If it goes outside memory, Windows will start using disk space as an extension to memory. This is, however, very much slower. If you run out of disk space, or have a fixed pagefile size, then your process will not be able to use more memory. If it's well written it will handle that, if not it will crash.
And for the main question, am I destroying my laptop a little everytime I do this?
No moreso than normal use. The ideal is that a processor rated for speed X can continuously run at that speed. It's not like a motor where they have a duty cycle of expected use 2-hours on 4-hours off, etc.
Of course, your specific laptop might have design flaws, poor tolerances, have a cooling system that can't cope with 100% full power, have component flaws, your software might have bugs, interactions of all the specific patches and versions and programs you have installed might cause odd behaviour...