Why would the front wheel bearings have to be replaced every week?

The installer doesn't says he doesn't know what the problem is. A mechanic is suppose to show up Monday evening (a friend of a friend) to check it out; I'll show him your response and hopefully he'll figure it out. You're very kind to help me, thank you so much for responding :-)

These bearings range in price from $25.00 to around $79.00 retail, so you be the judge of the quality by the price.// Just curious, have you actually seen ANY of the old bearings that were 'supposed' to have been replaced??? Ps, have the mechanic check the torque first, a loose hub retainer nut will sure cause this! Better a little to tight than to loose. Also, have him look to see if the bearing has indeed been changed!??? Or just tightened up!? Lot of the time a failing bearing can be retightened, this will last about a week then the noise will return. (Just a thought porbably wrong, i hope!) But something aint right here! Post the results. Thanks, pr.