In the pre-Obamacare debate of 2009, Congress recognized an important truth about health coverage: If people have no co-payments or deductibles, if they face no limits on doctor visits, surgeries and scans then … heath care costs skyrocket. Ultra-generous first-dollar coverage invites people to splurge on care. If it’s free, they’ll take the brand-name drug instead of the generic because, heck, someone else is paying. Enter the Cadillac tax. That’s the moniker for the effort, which eventually became part of Obamacare, to tame lavish, solid-platinum health plans enjoyed by millions of Americans — including, most prominent politically, some union members. Here’s how the tax works: In 2018, Americans with the most expensive employer-provided plans will face a 40 percent tax on plans that exceed $10,200 for individual coverage or $27,500 for family coverage. That is, for family benefits worth $30,000, the tax would apply to the $2,500 that is over the threshold. Thresholds will be higher for plans in designated high-risk industries or plans that cover disproportionate numbers of older workers or retirees. The Cadillac tax initially wouldn’t affect most people because its thresholds are relatively high: The typical individual plan last year cost $6,025 and the typical family plan $16,834, the Kaiser Family Foundation reports.