When buying a rental home after many years of our occupancy, is a home inspection still necessary?
Yes, unless you are an inspector yourself. Inspections often catch things owners don't know about. The owner may have maintained it meticulously, but he can only fix the problems he knows about. My home inspector caught a few safety issues like pitch of the exhaust from the water heater and a sharp edge around a flexible gas line in the fireplace. You should also plan on the house being inspected when you eventually try to sell it to someone. Inspections aren't expensive, but they can catch expensive issues. Mine noted the condition of some of the windows was poor and I was able to negotiate $2k off the selling price. When you have a home inspection, it gives you the power to negotiate a better deal for yourself.

As far as what level of inspection to get, I wouldn't hesitate to spend up to $200. So whatever that gets you, but that's just my opinion. 

Since it is a condo, I'd also be concerned about the health of the condo association's finances. Is the roof on the building 20 years old? Have they collected and saved enough money to re-roof the structure or will they require an extra $15,000 from everyone next year?