How do you build real leverage before walking into a vendor negotiation?

We used to lose hard on vendor pricing because we went in with no alternatives.

Bluffs never worked for us, and vendors could easily tell when we were stuck.

Recently we started spending time setting up a realistic backup solution before any big pricing talk.

Even if the backup isn't perfect having an actual alternative gave us the power to step away.

That single shift saved us 25% on our last deal.

What steps do you take before a negotiation to make sure walking away is an actual choice instead of a fake threat?