@Casey Dye In general, if the property doesn't cash flow then you should not invest as you are then investing on long term appreciation which is speculation. Additionally, if you are burning your reserves each month eventually you are going to run out of money to keep operating the investment.
All that being said, I have owned a few homes where it was a 'vacation home for free' rental model. So as long as it went between -$5k to +5k per year in cash flow (excluding tax/depreciation benefits), the negative years I accepted because of the other ancillary benefits of owning my own vacation home. We used it for 14 days per year for personal use and made as many 'maintenance' trips as needed (where we also enjoyed the home). One year, I was even able to leverage it as a trade where we wanted to stay at a beach house and offered a trade to that STR owner.
Long story short though, you never want to over-leverage and you really do want to have positive cash flow in most situations. In California, many investors end playing the long-term appreciation game with their STRs simply due to the high average cost to acquire vs net revenue.
Best of luck!