Cross that bridge when we come to it.

http://www.famousquotesabout.com/quote/We-will-cross-that/16270

Meaning: You can say "we'll cross that bridge when we come to it" if someone mentions a problem that might occur in the future, but you want them to think about what's happening now instead.

For example:

• Martin asked what we'd do if our new company couldn't find good staff when we needed to expand, and I said we'll cross that bridge when we come to it.
  
• Jenny worries too much about things that might happen in the future, so people are always saying "We'll cross that bridge when we come to it" to her.
  

Quick Quiz:

We can say "we'll cross that bridge when we come to it" if someone asks about

how to get over a river a future problem a failed business

Click for answer b.