Cashflow management on rental - create cont fund or reinvest?

[Cindy H.]

So we bought a rental, 30 yr amortization, monthly payments. Is it worth increasing payments to 2 per month, bi-weekly, making extra principal payments to reduce the mortgage? We've allocated expenses to everything we could think of so in reality our cashflow will likely be higher than our "estimate". Assuming we won't need to be doing repairs immediately and vacancy is 0% at the moment, should we just put that "extra" cashflow into a separate fund (earning no interest) or should invest any extra, then pull out (if liquid) or use our existing HELOC to cover any major expenses? How do you manage the cashflow on your rental?