Feed and water adults at least once per week. I usually give a half dozen or so appropriately sized prey items to each adult and make sure to top off their water dishes and mist where appropriate on a weekly basis.
Spiderlings can do fine on one feeding per week but will accept food more often than adults and many people feed them twice or even three times a week. This is fine and speeds up growth as well but it is not necessary. To determine the size of the prey item for the spiderlling in question I try not to go any larger than the total prey item not being greater than the size of the spider's cephalothorax. Some spiderlings will take much larger prey than this but most will accept prey this size readily. I don't count how many eaches I feed each spider but if anything is left uneaten the next day it is removed.
Captive bred spiders are always a better choice over imports when available. The reasons for this are numerous but the most important reason to the average hobbiest is that captive bred specimens lack the vast amount of internal parasites and all other kind of nasties that wild caughts can and do quite often come in with. Captive bred spiders tend to do better at eating on a regular basis, they seem to flick hair less often and just do better overall at surviving in your collection. Captive bred also have the advantage of not having depleted any wild resource. This is not to say however, that wild caught specimens are not needed in order to keep fresh bloodlines in the hobby. Without wild caughts we would be without many of the fantastic species available today. Before we start pointing fingers at how keeping wild caught spiders is wrong let's remember where all our prized specimens actually came from not too long ago. In addition not all spiders are easy to breed and some have not yet been successfully bred at all. With the way the world is going the survival of some species may some day be dependant on captive breeding. This will never happen without original wild caught specimens to start the whole process.
What you have is phorid flies or fungus gnats or some evil cousin of one of the two. They reproduce like mad on uneaten cricket remains which is part of why cleaning up uneaten remains is so important. The easiest and most effective way to combat these is to let the substrate in the container go dry and stay that way for a while. The flies dry up and die much faster than the spider will. Water must be provided to the spider during this time but dryness and cleanliness must be maintained. The bottom line is, if you leave dead crickets in your spider's container and/or keep the substrate wet like a swamp, then you will most certainly have an outbreak of these from time to time. They do not appear to prey upon or bother healthy tarantulas but weak, molting or injured specimens may be damaged or even killed by them. Keep your tanks clean and water in the dish instead of on the dirt and you can avoid these nasty little monsters.
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