How much negative cash flow is too much

[Bradley Shuhart]

I have an opportunity to assume a loan at 2.5% in a HCOL SoCal community. Even at that rate I will still be losing about $800-$1000 per month with a renter due to HOA & Mello Roos. I'm ok with a negative cash flow for a couple of years because its in an area that should continue to appreciate. My question is how much is too much negative cash flow? Is there a general rule of thumb or is it based on personal tolerance. Thank you!