I cut my teeth on my first purchase in 2017, a one mixed building with 2 commercial tenants and 2 residential tenants.

I got my teeth knocked out and my lunch money eaten on some of my inititial "deals".

Again, refresh your list every 6 months.Some specialty lists like probate I hit every other month and stop after 6 to 9 months.There are other time-sensitive lists such as expired listings or FSBOs which you may want to hit hard ASAP, like every other week for 6 to 8 weeks  because you know others are hitting those same prospects at that same time...A lot depends on the level of competition and the average value of a deal in your market - might do more or less often depending upon such factors....

I try to stick to non-time-sensitive refinance only in the non-qm space.

Cut my teeth a little by upgrading everything, however it is a very solid cash flowing building with low maintenence now!

Since when are debt instruments traded in a secondary OTC market not rate sensitive?

It is as rare as hens teeth and even if you found a deal like this it would be dangerous

This ties to what @Ryan Evans said of being hyper sensitive to location, which in up and coming areas is somewhat speculative, thus increasing the risk.

They can be very profitable but are also very fragile and sensitive to economic downturns like 2009 and right now. 

If you buy in Austin at current levels and we experience a significant recession even on the mild order of 2008 then there will be a lot of nashing of teeth for new investors.