How many properties should you hold in one LLC or LLP?

There is no correct answer here.  This is all about your personal tolerance for risk.

However, the purpose of an LLC/LLP structure is asset protection.  The overall strategy should be to segregate assets.  Therefore, if you have all of your properties held in just a single LLC/LLP entity and you are sued, all of the properties would be subject to a judgement creditor in a court approved claim against you. With that in mind, is it wise to have multiple properties in a single LLC/LLP?  Many individuals will do so because they do not want to pay the annual fees and deal with the administration of multiple LLC/LLP entities. In the long run though, it would be in your best interest to break up the assets into separate LLC/LLP entities and just view the additional annual fees as added “insurance” in the event of a lawsuit. In this scenario, if you are sued by a tenant in one property, and this property is the only asset in the LLC, then the tenant cannot reach into your other LLC/LLP entities and make a claim on them.

Again, there is no right or wrong answer here.  It all boils down to personal preference.