The trade itself is solid, and your buddy's not exaggerating - people do always need their pipes working. But here's the thing nobody warns you about: the first 2-3 years are brutal. You're looking at an apprenticeship where you're basically the grunt, making way less than you do now in retail management, and you're hauling 50-pound boxes up basement stairs at 6 a.m. Some folks bail during that stretch because the pay cut hits harder than they expected, especially if you've got rent or a family depending on your income.
That said, once you're licensed and build a client base (which your buddy has clearly done), the money and flexibility are genuinely different from what you get in management. You're not stuck answering to a district manager about scheduling, you control your own hours way more, and emergency calls mean overtime rates that actually add up. The key difference from retail: you own the skillset, not just the schedule. There's real leverage there.
The pitfall to watch? Make sure you can actually handle the physical grind without burning out. It's not just the heavy lifting - it's crawling under houses, working in freezing basements, dealing with sewage. Your buddy probably loves it because he's built for that work. And check your local market before jumping in. A plumber killing it in a big metro with aging infrastructure isn't the same as someone in a growing suburb where new construction work dries up. Talk to a few local plumbers about where they're actually getting calls from, not just your buddy.