Climbing access is already a tense situation don't make it worse. The most important thing to remember is the leader must not fall, so climb within your limits. Camming devices and nuts are usually solid on the Navaho and Wingate, but on softer rock like Entrada, a good fall will blow out the rock, causing the placement to fail. Never trust your life to just one piece. I have talked to climbers that have claimed to have pulled three TCUs in a row on Wingate.
Wise man say sew it up and live long.
When aid climbing try to use clean placements whenever possible, when removing pitons clean in an upward motion, so as to create a possible nut placement. Don't get in over your head, don't bolt on established routes just because you are unworthy. This is not Yosemite you will be lynched for such a travesty here. Use extreme caution when rappelling off fixed gear. Check the bolts, you may live longer.