Originally Posted by Digital Gee
1. How often should I check the air pressure on the tires? Do I need to have a tire pressure gage with me or can it be judged by either the gas station's machine or by hand?
All tubes seep a bit of air. Some tubes leak faster than others. My MTB tubes leak very slowly. My roadbike tubes lose about 2-3 PSI every day. I top off my tyres to the proper pressure before every ride. I have a high-quality floor pump with an attached pressure gauge. For MTB tyres, I can usually judge by hand. For pavement, I run it up to max pressure. For dirt, I drop it down to around 40PSI. Gas station pressure gauges are suspect but if you're off by 5 PSI or so, it's not going to be the end of the world. For roadbikes or if you have higher pressure tyres, you'll need to carry a gauge since gas station gauges don't typically register up that high. I have one from Topeak that works pretty well.
Originally Posted by Digital Gee
2. The LBS offers lifetime free adjustments and said I should bring it in once all the cables have loosened up so they can be tightened; about how many miles would you suggest before I do that?
My LBS says sometime between 50 and 100 hours of riding but as another poster has said, you'll know when things go out of adjustment so just take it in when things degrade.