Getting them to raise their credit card limits to attend their seminars, purchase their CD's, and go on their bus tours. 

So, for every 10 contracts, only five of them close.

Now since you mentioned Property lines of Credit or Business lines of Credit are we talking about Credit cards?  

I have paid off student loans, my house, credit cards, car and have 100k that i would like to invest.

Our average tenant stay exceeds five years, and we've had just seven evictions in over 16 years out of more than 1,000 tenants.

And as long as you've lived in it for two out of the previous five years, get the 121 exclusion.

I would open up a few more credit cards.  

I started in 2016 and within five years I had over 30 units and 135 self storage units earning $150,000+ per year.

I would assume little to no appreciation over next five years so I would model it and see where it plays out

Then what happens on paper a property looks like a cash flows very well, then when you add in vacancies repairs and life in general, they end up having to start using credit cards to pay for things and get caught into that spiral To answer your original question most real estate investors are not buying a property every year.