This is the “show your work” post in the series. If you came for the FIRE strategy you can happily skip it; if you want the Roth conversion optimization written out as an actual linear program — decision variables, constraints, objective — this is for you. It mirrors the Excel + OpenSolver model I described in part 2.
Continue reading “The Roth Conversion Math: A Linear Program”How Much Should I Convert to a Roth Each Year?
This post is about a question I keep circling back to as an early retiree: how much to convert to a Roth in any given year. Not whether to convert — I’m already sold on that — but the actual dollar amount, year by year. It turns out to be a surprisingly good little optimization problem, and this is how I think about it.
The Roth Conversion Ladder (and Its Blind Spot)
If you retire before 59½ with most of your money locked in a traditional IRA or 401(k), you run into an awkward problem: the money is there, but reaching it normally means a 10% early-withdrawal penalty on top of income tax. The Roth conversion ladder is the classic FIRE workaround, and it is the setup for everything else I want to write about in this series.
Continue reading “The Roth Conversion Ladder (and Its Blind Spot)”Last Mile Route Optimization (Free Tool)
Ask any delivery operation where its money actually goes and the honest answer is almost always the same: the last mile. Trucks leave the depot full and efficient, and then it all unravels at the end — one driver zig-zagging across a neighborhood, doubling back for a stop they rolled past twenty minutes earlier, idling outside an address that doesn’t open until noon. Last mile route optimization is the work of squeezing that final leg down to the least driving, the fewest miles, and the most stops actually served. I spent two decades building optimization models for exactly this kind of problem, and I eventually turned one of them into a free tool. Here’s why the last mile is so stubborn, and how a solver beats a map every single time.
Continue reading “Last Mile Route Optimization (Free Tool)”Chase Sapphire Reserve Authorized User Benefits
Chase Sapphire Reserve authorized user benefits come up a lot when someone wants to share their travel perks — or quietly hopes adding a family member will lift that person’s credit. Both are reasonable goals, but they pull in different directions, and the answer to “is it worth it” depends entirely on which one you’re chasing. I sell authorized user tradelines, so people bring me the credit version of this question all the time, and the honest answer is more interesting than the card’s marketing.
