I've listened to the BiggerPockets podcasts and what always seems to evade me is how people go from their first investment (or first few) to the next handful.
I've followed much of the advice (bought my primary residence in Denver, CO in 2012 for $320,500 and have rented out the basement consistently since then effectively living for free - yay house hacking!).
Two years later, in 2014, I bought a $91,000 condo for ~$20,000 down of my own cash, rented it for 2 years, making ~$200 a month. In a growing market, I sold it 2.5 years later in 2017 and did a 1031 to buy a 3 unit apartment building in Rhode Island for $274,000, with about $8,000 of my own money down.
In 2015, I bought a 4 br/2ba house for $200,000 with a $35,000 HELOC on my primary residence and $15,000 of my own money.
In 2018, I bought a 5 br/2ba house for $335,000 and put about $50,000 into renovating it (including adding a 3rd bathroom). I used a HELOC on my primary residence for the down payment and renovation costs and brought in a 5% partner. I'm in the middle of refinancing it now, although won't get out a TON of cash, some, but not a life-changing amount. I'm creatively renting this place by the room, and making ~$4,000 in rent a month, which I know isn't the 2% rule, but cash flows about $1,500 a month, so I'm happy with that, which I liken to house hacking, but for an investment property.
Here's my question - I've got 4 properties (including my primary residence), which is wonderful, but I feel that I've leveraged the majority of my equity, until I'm able to pay down more of my existing HELOC. I've inquired about getting a HELOC on my 2015 investment property (my interest rate is 3.875% so a cash-out refinance doesn't make sense), but HELOCs on investment properties are ~Prime + 4.5%, which is pricey. I love hearing how quickly people have been able to take one property and transfer it into a small portfolio of 10+ properties, but I'm a bit befuddled as to how to move beyond where I am right now, other than aggressively paying off my HELOC to free up those funds for another down payment.