You'll know when you can't communicate over a reasonable range. The right question is how do you test for RF problems.
- Substitution. Find a known working wireless router or client radio and do some testing. For example, if your laptop radio seems sick, then take it to a known working wireless router (i.e. coffee shop hot spot) and do some testing. If your wireless router seems sick, have a friend with a known working laptop test it for you.
- Use Netstumbler on a 2nd laptop to disclose the measured S/N ratio and signal strength numbers. High noise levels usually means interference.
- An expensive pile of test equipment. TX power is easy using a dummy load and spectrum analyzer. RX sensitivity is not so easy but doable with an 802.11b/g test source and precision attenuator. A sloppy way to test the receiver is have it scan for nearby access points and compare results with a known working radio.
Now that you've found this group, all me inform you of your indiscretion. You didn't bother mentioning the model number of your $35 Netgear whatever. If you're expecting sympathy, you've done the right thing. If you want technical help, kindly disclose what problem you are trying to solve and what hardware/software you have to work with.
"Crap out" is not terribly descriptive.
Perhaps a diaper or enema would be helpful.
Reliable, fast, cheap. Pick two. This week, I'm partial to Linksys WRT54G with Sveasoft Alchemy replacement firmware. About $70 before rebates. I've also had fairly good luck with Netgear WGR614, although the radio range is not quite as good as some others. About $50 before rebates.