How to assess a deal (sell it or lease it?)

[Stephanie Z.]

When deciding whether to sell or lease a commercial property you own (but no longer need), what are your deciding factors? 

For instance, say the value to sell is $500k, and the potential 10 year NNN lease rate is $5k/mo, making it a 12% cap rate. (Assume same new user is offering to either buy or lease, at your choice.)

What other factors besides cap rate do you consider? Quality of tenant? 

How do you determine the fair annual rent increase? Is there a norm? 

If you provide options to renew (say three 5 year options), how do you determine the rent rate in those future options? Is that rent generally controlled by the deal you set in the original 10 year lease? If not, how is it determined? Is there a norm for valuing these options (do they impact the rent amount)?

How sale-able are properties like this once they are leased? Are they best sold with the lease in place (as I know often happens with residential rentals) or are they best sold empty? 

What professional(s) are best to advise a small time investor on these sorts of decisions? 

Anything else to consider?

Thanks for any tips or links you can provide!