When you later sell that property you will not get the full amount of gain tax free as with your other primary residence. 

I can't remember exactly what it was, but something about that book gave me the idea that apartment complexes/multifamily homes are the ultimate form of passive income.

And I'll turn that into 10-15% gains, or much more...

Reap the benefits of what you have gained so far, most likely almost tax free.

@Dimitri Bernado You have to determine how active/passive of RE investor you want/can be, pick a niche within RE investing, learn as much as possible about it, network with other investors, and start investing. 

I like to know everything I need to know and gain tips and advise on how to find a starter homer hat meets most of my needs. 

This is commonly referred to as the BRRRR strategy.If you are looking to grow a portfolio to gain passive income to replace your current income this is a perfect strategy to use.  

I’m exploring this site and real estate in particular as a way to increase our cash flow, ease up our responsibilities and increase our choices in how we live our lives.I’m particularly interested in multi family investment properties, first to move my 22 out of my house (anyone familiar with Denver will know the housing cost situation here is tough), and second for passive income streams and equity building for my children’s future. 

I am not necessarily saying you have to use all of your gains from the primary residence for a new property. 

I will list the numbers:current rent $1950/month (going to $2000 in about 6 months at end of 2 yr lease)My expenses: annual taxes $7950 ($662/month)                        Heloc balance $170k interest currently 5%                        land lord policy $1150/ year                        Self managed                        Maintenance : has averaged $300-400 per year.Reasons I am considering sale :   1) property is currently worth about $270k (making me feel roi is low).                                                           2) property has a pool which is a liability that I'm not completely comfortable with.                                                           3) property has a heloc balance against it of about $170k that I technically cannot deduct the interest                                                                       because it wasn't used for the property or any other rental.                                                           4) Tax treatment: my understanding is if you sell it having lived in it 2 out of last 5 years the capital gains                                                                 would be exempt.