Safe Down Payment Reccomendations?

[Jason Stern]

When it comes to buying multifamily homes, whether be duplex, triplex, quads, etc... What is the recommended percentage you should put down to be conservative, not over extend yourself, ensuring good probability of no financing hiccups? 

I know the best put as much as you can but if you are trying to keep cash in pocket, what would be the minimum to play the game safe?

That being said, My wife and I both bring steady income consistently that doesn't fluctuate.

Not trying to hit a home run with cash flow just trying to hold for long term retirement income but want to invest safely so I don't the carpet swept from under me. 

Thanks BP nation for reading!

Jason