Potential hires sometimes ask how much runway we have left. We have 6 months of total runway, but need about 3 months to prove our assumptions and start showing real traction. This leaves us a 3 month "raising runway" for the series A.
The best way to get more raising runway is to prove faster, which we can sometimes do by spending more money. Our expenses are roughly $30,000 a month. If we get to validation a month earlier by spending $15,000, total runway is reduced by 2 weeks while raising runway increased by 2 weeks.
There are lots of opportunities to spend more money wisely. Whether hiring a consultant for a few hours or buying a dedicated machine to avoid re-architecting, the amounts can vary from a few hundred to a few thousand dollars.
I hear a lot of people claim startups aren't "lean" if they spend a lot. The whole point is to learn as fast as possible on the smallest total budget.