But what are the pros and cons associated with a student housing investment compared to a traditional buy-and-hold investment where you're not renting exclusively to students?

If OP pulls out for some reason before the parents die, the current owners could lose their 2 of 5 year gain exclusion.  

@John ClarkAre you referring to the annual gift exclusion?

I don't think it is terrible, but if you rely on it exclusively, you might be way out of market.

Let's say you hoise hack and 1031 your way up to multiple properties and you finally use one of the homes as your exclusive principal residence and sell.

My wife and I are approaching 2 years of ownership and use of our only home as our primary residence in which case we should qualify for full $500 exclusion of capital gains upon sale.

I am familiar with the rule around the capital gains exclusion for your main home, in that you must live in the home for 2 of the last 5 years, but those years don't have to be consecutive nor do you need to currently live there. 

Does the fact that it is our son's primary residence allow us to use the primary residence exclusion?

", then lose them.Also, never sign any exclusive agreement with any agent. 

Google Sec 121 Cap gain exclusion.