DEAR BOB: I enjoyed your recent discussion on the tax benefits of property depreciation. We just bought our first home for $42,000. How much can we depreciate it each year? Hanna B., Rockville.

DEAR HANNA: Sorry, but your personal residence is not depreciable for income tax purposes. Depreciation is an expense deduction only for property held for investment or for use in a trade or business. However, if you use part of your home as an office or shop, or if you rent part to tenants, then depreciation applies to that portion. Check with your tax advisor for more details.

DEAR BOB: We want to invest in apartments. We found an "advisor-broker" who, for $500, offers to guide us through all the details of finding a property, negotiation and sale closing. His fee if refundable if he splits the purchase commission with another agent who has the listing. But if there is no broker (direct sale), the agent wants us to pay him a 4 per cent commission. This contract is to continue for five years and includes all property we buy in that time. Is this a good idea? Lisa P., Alexandria.

DEAR LISA: Real estate counselors perform valuable services that can aide property buyers and sellers. Fee arrangements vary widely. But be sure your "advisor-broker" is a member of the American Society of Real Estate Counselors. If not, look elsewhere.

Frankly, I don't like that five-year contract. I shouldn't be necessary to tie a client up like that if the counselor is doing a good job. For a list of real estate counselors in your area, write to the National Association of Realtors, 430 N. Michigan Avenue, Chicago, III. 60611.

DEAR BOB: My land deed says a structure can't be built within 35 feet of the street. The development company has been defunct more that eight years. But the city ordinance requires only 20-foot setback. Will I have any legal problem if I build 30 feet from the street?Frances A., Annandale.

DEAR FRANCES: You may. Consult a real estate attorney. Deed restrictions not only benefit a developer, but also nearby property owners who can often enforce such restrictions in court. You may also encounter difficulty getting a mortgage if you build in violation of deed restrictions.

DEAR BOB: How can I collect rent from tenants who moved out without giving proper notice? William D., Washington, D.C.

DEAR WILLIAM: In most areas, small claims or housing courts are available for settling landlord-tenants disputes. No attorney is needed.

DEAR BOB: When we recently listed our home for sale, the agent said she would phone us for an appointment when she had a prospect who wanted to inspect the house. Yesterday when she phoned, she asked if we could be away while she showed the house. Isn't this unusual? Kathy B., Bethesda.

DEAR KATHY: No. Your agent gave you good advice. Get lost while she's showing and selling your house to prospective buyers. Home sellers often ruin sales even though they're just trying to be helpful.

If the seller is nearby, buyers feel rushed and may not fully appreciate a home. Your agent is an expert at selling homes. You're not. Let her do her job. Alone

DEAR BOB: We own 10 acres in Quebec that we want to sell. How can I find a real estate agent here to sell it? Dwayne M. Annapolis, Md.

DEAR DWAYNE: You probably can't. Write to the realty board in the city nearest your land for their list of agents specializing in land sales. Then contact those agents and list with one who can market your land.

DEAR BOB: What does it mean when a home for rent is advertised as "rent with option to buy?" Marcia B.

DEAR MARCIA: Home sellers who encounter difficulty selling their home often decide to rent it and gave the renter an option to buy it later, perhaps in 12 months. To practically assure a sale, smart owners give full credit toward the purchase price for the year's rent paid. Few renters can resist buying a home for which their rent is credited toward the down payment. Such arrangements are good for both the buyer and seller.

DEAR BOB: If we spend money improving our home for eventual resale profits, are the improvement costs tax deductible? C. M., D.C.

DEAR C. M.: Capital improvement cost are an addition to your home's cost basis. There is not immediate tax deduction for such expenses.

For example, if you spend $5,000 for improvements, add that $5,000 to your home's cost basis. When you sell, your adjusted cost basis is subtracted from the adjusted sales price (gross sale price minus sales costs) to determine your capital gain profit.

DEAR BOB: I recently sold some land and gave the deposit to my lawyer to close the sale. He wrote me that the sale fell through because of an old right-of-way on the land that can't be cleared. He also sent me his $75 bill for the title search. Isn't the title search the buyer's cost? French F., Bethesda, Md.

DEAR FRENCH: Title problems are usually the property seller's responsibility to clear up. To remove the old right-of-way easement may require a quiet title or other appropriate court action. Until you clear this title problem, your land probably won't be bought by anybody. Hire a good real estate attorney who is a title expert to get your title problem solved.

DEAR BOB: Several times you've talked about "taking back" a mortgage. I've looked in a real estate dictionary and can't find that term. What does it mean? George V., Frederick , Md.

DEAR GEORGE: A "take-back" mortgage is one that the property seller taked back to help finance the buyers purchase. For example, suppose you buy my home for $50,000 with a $10,000 cash down payment and I agree to "take back" a $40,000 mortgage for you. Property buyers should always remember the seller is their best source of first or second mortgage "take-back" financing.

DEAR BOB: I've heard that if a real estate investor, such as myself, sells more than five properties per year, the profit is taxed as ordinary income instead of as long term capital gain. True? Alma A., Hagerstown, Md.

DEAR ALMA: Sometimes. A "real estate dealer" is a property owner whose properties are held as inventory for sale to others, such as a home builder. His profits are ordinary income, not long-term capital gains.

It's often hard to distinguish between a realty dealer and an investor. IRS uses criteria such as (a) number of transactions per year, (b) holding time of each property sold, (c) subdividing or making property improvements, (d) taxpayer's other income (if realty sales are not his main business). Each sale depends on its unique facts. By the way, it's possible to be taxed as a dealer on some sales and as an investory or other sales. Your tax advisor can give you more details.

The new report, "How to Use Creative Realty Finance Ideas for Profit," is available for 25 cents in coin plus a STAMPED self-addressed envelope sent to Robert J. Bruss. P.O. Bos 6710, San Francisco, Calif. 94101.