DEAR BOB: I just passed my real estate sales license test and am considering which brokerage office to work at. I've narrowed the choice to two. Both are respected firms here. One has a franchise from a national firm, the one that advertises on TV so much. The other firm doesn't advertise much, but according to the broker, all the sales agents earn at least $16,000 a year. He says they do this by keeping their listings "in the house" and don't use the multiple listing service. Which firm do you think is best? Kitty R., Frederick, Md.

DEAR KITTY: Real estate is apeople business. No matter how much money is spent on fancy ads, sales aren't made without good local people. While there are advantages of working on an office with a national franchise name, most agents working in those offices earn about the same as real estate agents working in non-franchised offices.

But I think twice about joining the firm that doesn't use the local multiple listing service. This is a system used by member agents to distribute their listings among all cooperating agents. It leads to greater sales volume for agents and the best sales price and terms for the property sellers. It would be a big handicap to work without a multiple listing service. If all other factors are equal. I'd avoid working for a broker who doesn't use the service.

DEAR BOB: What depreciation methods are now available under the new tax law? Lewis L., Arlington.

DEAR LEWIS: The 1976 Tax Reform Law and the 1977 Tax Reduction Act didn't change permissible depreciation methods for real estate.

New residential housing, such as apartments, qualify for either the 200 per cent double declining balance or sum-of-the-years' digits methods. These methods give minimum depreciation deductions in the early years after property purchase.

New commercial property qualifies for the 150 oer cent declining balance depreciation method.

Owners of used residential housing can use the 125 per cent declining balance depreciation method. All other depreciable property qualifies for only the straight line depreciation method, which can also be used on any of the property types discussed above.