"What's this?" grumbles Andrew D'Amato, squinting at a minuscule droplet of wet paint on a windowsill. He steps back for the wide-angle view. "Man!" he mutters as he spies a half dozen more all-but-invisible paint beads clinging to the window's casing. Striding around to the side of the house, he buttonholes the offending employee. "Front of the house, to the right of the door?drips!" he says tersely. The worker trots off toward the site, double-time, as D'Amato shakes his shaggy head. Among the many chores that humans tend to botch or rush, repainting a house's exterior must rank near the top. The word slapdash, denoting all acts hurried and shoddy, could have sprung precisely from the near-universal tendency to slap pigment on a weary clapboard, then dash off to do something more thrilling. While this tendency is regrettable, it's also understandable. The perfect metaphor for an endless, grueling task is a lone house-painter staring up at a three-story Victorian replete with mildewed shingles, peeling muntins and alligatored filigree. Exhausting labor, dizzying heights and the specter of lead poisoning?no wonder average mortals blanch. But D'Amato, co-owner of Andrews Painting in Milton, Mass., actually enjoys painting, and he cares deeply about tiny drops on a huge house. "Painting is the last step in the construction process and the most dramatic," he says. "The change we make is very satisfying." Over the past 15 years, D'Amato, partner Andrew Lieberman and their crew have attended to dozens of grand old houses throughout greater Boston. "Our clients care about their home," D'Amato says. "It's more to them than a place to plunk. It's a showpiece. That's why they love us." A graduate of the Art Institute of Boston, he took up house painting to repay school debts and discovered his affinity for it. Today's project is in Milton, at D'Amato's own house, which he and his wife began renovating three years ago. With an expansive front porch and gorgeous fretwork, the circa-1865 house has awesome potential waiting beneath a striated, peeling, moldy, graying skin. "I'm sure it hasn't been painted since the '50s," he says. Which made him eager to get started. But the first requirement of any job is patience. D'Amato never paints an exterior before June. "The long winters in New England saturate wood, especially exposed wood like this," he says. Atop a 24-foot ladder, he pulls a battery-operated moisture meter from a pocket and presses the meter's two prongs 1/4 inch into a clapboard high on the house's north side, typically the last spot to surrender its load of spring rain. "We like the moisture content to be under 12 percent. Here it's 10, so we're OK." Time to paint? Not so fast. The most important single lesson about top-notch house painting is that more than half the job is not painting. "It's preparation," D'Amato says. "When we hire people, we tell them that prep is most of it. They say, 'Yeah, yeah, yeah, I know.' But as the days go by on the job, they say, 'I'm sick of this?I've got to paint something!'" D'Amato is generally an affable guy, but he never bends on this point. "I tell them, 'I think you need another job.'"