Alignments on my W124 hold a long long time. I know people on this forum turn up their noses at Firestone, but their lifetime alignment is a pretty good deal, especially if you can get it on sale. I'll probably be getting them to do it on my W210 when I get new tires (not noticing any pull, though).

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14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 160k miles
06 E320 CDI "Rutherford", Black on Tan, 180k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 145k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 79k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife