I call transactions with related parties incestuous. So an incestuous 1031 is between related parties. 1031's shift basis between the assets. The basis shift doesn't work if either 1031 asset is disposed of within 2 years. (1031(f))
For those clients with a considerable real estate portfolio, the planner should see if there are any assets with a high basis that will be held long-term which could be exchanged for other realty in the portfolio with a low basis, thereby restarting depreciation and reducing gain on a later sale.
Simple example: Client owns vacant land with a $1M FMV and basis and no mortgage, as well as an apartment building with a $1M FMV and low basis and no mortgage. Client shifts the apartment building to an LLC taxed as a partnership with Client owning 99% and then exchanges the land for the apartment building. Client gets to restart depreciation with a $1M basis in the apartment building.