Depending on the jurisdiction, but more often than not a sheriff has to be present during an eviction.
Either way, the law is almost never on your side.
Having good tenants on the other hand who pay on time and give minimal hassle are a godsend. There are landlords who haven't raised the rent on these folks for years because they are so rare and they (landlords) don't want to lose them as tenants.
Our tenants over the past twenty years have bought us two houses (we occupy one, they rent the other, one lot), by reducing our "rent" (our portion of the mortgage, taxes and insurance) to less than $500 per month. We renovated ten years ago and increased the rent by two-thirds. We have replaced a couple of appliances, had service calls for maintenance and repairs on systems, but our tenants do the upkeep (painting, small repairs, etc.). Overall, the occasional headaches have been worth it as the property value has more than tripled over the past ten years.