Environmental: the EPA lead renovation rule for every pre-1978 home, and asbestos before you cut into an old ceiling
In one paragraph
Two federal and state rules follow you into any house built before 1978: the EPA's lead renovation rule, which requires your firm to be EPA-certified and your people trained as certified renovators before you disturb more than six square feet of painted surface in a room (or twenty outside), with the Renovate Right pamphlet handed over first and the lead-safe work practices used; and the asbestos rules, under which the air district requires an asbestos survey before renovation in the South Coast basin, Cal/OSHA's construction standard governs any disturbance, and a contractor doing 100 square feet or more of asbestos work must be registered with Cal/OSHA. An electrician cutting boxes into old plaster, pulling a popcorn ceiling for cans, or opening an old panel wall is inside both rules more often than not. The lesson gives the thresholds, the paperwork and the estimate line.
The rule
Under the EPA Renovation, Repair and Painting Rule, renovations in housing and child-occupied facilities built before 1978 must be performed by EPA-certified firms using certified renovators following the work practice standards, with the Renovate Right pamphlet delivered before work begins (40 CFR 745.84, 745.85, 745.89); minor repair and maintenance, including electrical work, that disturbs 6 square feet or less of painted surface per interior room or 20 square feet or less outside, without prohibited practices, window replacement or demolition, is exempt (745.83). Asbestos-related work of 100 square feet or more requires registration with Cal/OSHA (Labor Code 6501.5); 8 CCR 1529 governs any construction asbestos exposure; and in the South Coast district a survey and notification precede any renovation (Rule 1403).
Why it matters
Much of the housing you will work in predates 1978, and the lead rule turns a routine 'cut in six new cans' job into a certified-firm job with containment and cleanup that has to be priced. The asbestos rule is the one that stops work: a popcorn ceiling in a 1965 house is presumed to contain asbestos until a survey says otherwise, and cutting into it without one is a health violation, a rule violation, and a liability that follows the contractor, not the homeowner. Both are estimate lines you add the day you see the year built.