Landlording is different.  In landlording it is often good business, for a variety of reasons, not to do everything yourself. You know what expertise you have, and you know what you are capable of doing both physically and mentally.  Can you do this job?  It may necessitate climbing up the side of a two-story building on an extension ladder that sways in the wind.  Are you afraid of heights? It may involve knowledge of the latest tax laws about exchanging. Have you been keeping abreast of the field? It may mean testing electrical connections with the power on.  Do you know enough about electricity to avoid electrocuting yourself?  If you suspect that you cannot do the work properly or at all yourself, hire it done.

Do you want to do it yourself?  Some jobs, like cleaning ovens, painting bedrooms, mowing lawns, and unplugging toilets, are tedious or repetitious or mundane or loathsome, and you may have no desire to do them yourself even though you know that you are able to do them.  If you simply do not want to do them yourself, hire them done.

Do you have time to do it yourself?  There are only 168 hours in a week, and even though you at times think you are superhuman, you cannot cram any more hours into your week.  If you do not have the time to do a job, hire it done.