The break even math changes a lot once you factor in what you actually do with the money. I pulled 40k out in 2018 at 5.25% to buy another place and that worked out fine, but if you're just sitting on the cash or using it for stuff you could save up for, waiting almost always wins. My lender kept pushing me to take more out and it took me a while to realize they don't care about my spread, they care about their fee. Run the numbers both ways with the actual rate you'd get today versus what you'd pay waiting a year or two.

My buddy Marcus ran into this exact thing last year at his chair in Austin. Client had 10 months of black box dye grow out and he did foils on one half, freehand on the other, and the freehand side blended out so much cleaner at the line of demarcation. Foils kept grabbing that old pigment deposit and leaving a hot band right where the two colors met, even with lower volume. For heavy box dye buildup freehand gives you way more control over where the lightener sits, but I still keep foils in my back pocket for fine hair where I need the lift to stay off the scalp.