If it's expensive and has a high annual fee, then talk to some professionals (CPA, Attorneys). 

Im $140,000 in debtNOI:  $6,944.00Cash on Cash ROI:17.56%Monthly Cashflow:$439.09Income-Expense Ratio (2% Rule):1.96%Total Initial Equity:$94,000.00Gross Rent Multiplier:1.89Debt Coverage Ratio:4.15Purchase Cap Rate:27.78%Pro Forma Cap Rate:5.79%

I also love YNAB for personal budgeting and use it religiously (knowing your income/expenses to the penny is key to profitable money management), so for the past few months I've increased my savings by pretending I'm carrying a note on a BRRRR and paying money into an account as if I'm in the middle of a 6 month rehab phase.I recommend that if you haven't laid out a business plan yet, grab a pen and paper and start mapping out your goals and how you'll get there. 

Purchase price: $125,000 (assuming offer is accepted)Down payment: $25,000 (20%)Financing: 30 yr @ 5% = $540 /moInitial rehab: $5,000Closing cost: $2,0001st yr Insurance: $1440Taxes: $120 /moInsurance: $120 /moVacancy: $150 /mo (8%)Maint/Cap-Ex: $270 /mo (15%)TOTAL EXPENSES: $1200Rent: $450 /unitTOTAL INCOME: $1800Cashflow: $600 /moCash on Cash: 21.5%Here is a link to the listing if it may provide more insight:Quadplex ListingThe unit is located on a decent street in a very small town (<10,000).

Assuming there are no looming big ticket items that I am aware of, would you/should I continue to save for reserves, or just maintain that reserve and replenish as expenses arise?

I agree that insurance cost is likely to be a bigger factor as far as expense goes, although that has already been the case, at least in the areas of central Florida I'm aware of.  

I currently live in SF, so I understand the difficulty of finding deals in expensive markets. 

Good that it's not a more expensive mistake.

or is it just too expensive?

If it is just the business and not buying a building or the land beneath it then it is not generally a real estate licensed activity.You need to check for each state what is or is not required.You could go on a site like Rocket Lawyer etc. and for a nominal fee ask the question.In commercial real estate transactions you can generally have consulting and other fees on the HUD-1 as RESPA does not typically apply.To look for more businesses you could look at bizbuysell.com  Sellers typically want 3 times gross profit earnings so if 100k a year after expenses they want 300,000.