Me: No.Caller: I'm the plumber who helped your tenant at your house next door to the one you're now renting.Me:  Oh yes (Kevin is the so-called "plumber" my non-paying tenant talked into digging up her sewer line in the pouring rain...without my permission...when they clogged it a month before they left without paying me my last months rent back in November. 

If he balks or tries to show without permission, that is when the lousy housekeeping strategy comes into play.

If and when a tenant states they want to vacate early, I give them written permission to break the lease without penalty.

If not, you could ask your landlord for permission. 

., Michigan, it is permissible for tenants to withhold rent if there is a MAJOR issue with the property.

And you then have permission to rent out the rooms to other people - to sublet? 

You can put them down as a long-term guest with your written permission which can be revoked at any time, if that person creates a problem. 

Do the parents get a key, heck yes, if they want one and are local, that is with the kid's permission which is never unreasonably denied (LOL).

No need to get permission or work out a convenient time, if she's not responding. 

I gave the sublet tenant written permission to be a long-term guest over the summer.