I triple-checked my math last night and yours today, and it takes 10 years of paying $35 per year plus $150 one time for 150 extra icon slots to break even with paying $50 a year (which includes 250 icon slots per year) for ten years:
$50 x 10yrs = $500 (premium paid account, includes 250 icon slots) $35 x 10yrs + $150 = $500 (regular paid account, includes 100 icon slots, plus a one time $150 purchase of 150 extra icon slots)
In your 11th year on DW, you will finally come out ahead by buying the icon slots once plus the cheaper paid time each year.
no subject
$50 x 10yrs = $500 (premium paid account, includes 250 icon slots)
$35 x 10yrs + $150 = $500 (regular paid account, includes 100 icon slots, plus a one time $150 purchase of 150 extra icon slots)
In your 11th year on DW, you will finally come out ahead by buying the icon slots once plus the cheaper paid time each year.
Nice graph, though. :)