How long do I wait before I open a dispute?

Recently ordered from a reputable german vendor, who usually ships out really fast. Packs usually arrive after 4 days max.

Its been about 10 days now and still nothing. Asked for tracking few days ago, vendor doesnt reply.

I extended the AF Timer and asked for tracking again. Nothing.

I really want to open a dispute but dont want to be a annoying customer.

When is it "okay" to open a dispute? I know vendors can be quite busy but I cba waiting any longer.

Wait until the AF timer is about to expire, then dispute.

That way you gave the vendor more than enough time to respond.

I would say extend as much as you can, once you couldnt extend more dispute.

I wonder this myself... I'm fairly new to all this but ever since I started buying on the DW it has been one thing after another. Luckily I haven't actually lost any money yet. Though I was waiting over three weeks for one order that I should got after 2 or 3 days. I opened one dispute after 3 weeks because the seller wasn't responding to my messages and once I did he got very active, though his tracking showed the package had never left his country so I got a refund by mutual agreement. So far I've made about 9 orders, all have taken longer than anticipated in delivery, only one didn't get here and I have 2 outstanding (1 late domestic, 1 EU which still has time to be fair to them). Apart from the stress of waiting and uncertainty, it has been reasonably successful for me. Ironically it's the domestic orders that are causing the most stress.