When you hire a broker, you will be asked to sign a listing agreement. Here's what it covers along with what may or may not be negotiable.
Since an agent doesn’t get paid or recoup expenses (on advertising, for instance) unless and until your apartment sells, most will insist on six months to feel confident the job will get done. In rare cases, if your apartment is obviously “special” enough to sell quickly, or for a very high price, this time period may be negotiable.
Antitrust laws dictate that there can be no “standard” or “required” commission—in other words, commissions are legally negotiable. That being said, agents are not required to accept less than what they ask for, which, in Manhattan has traditionally been 6% (split two ways if another broker brings in a buyer). In today's sellers' market, many agents may agree to reduce their commission to 5% (or even 4% if the eventual buyer is not represented by a broker). Anything less is very rare in Manhattan except in higher price ranges (multi-million dollar properties).
Keep in mind that getting your agent to agree to a 5% commission is not necessarily a good thing, because it reduces the amount the buyer’s broker will receive in a “co-broked” transaction from 3% to 2.5%. (That may not sound like a lot expressed as a percent, but on a $1 million sale, it’s $5,000.) If an agent is taking a buyer to see 10 properties that are offering a 3% co-broke, that agent might not even bother to show the one that only offers a 2.5% co-broke.
You will be asked to sign an “Exclusive Right to Sell” agreement. That means the agent will get paid the commission agreed to no matter who finds the buyer. So even if you find a buyer yourself, you still owe that commission, unless you have negotiated some limited exceptions.
"Co-Exclusive” agreements--where you will hire two brokers to work together--most often occur in the ultra-luxury market, and can happen when the seller believes that for an eight-figure property, the broker may be more likely to find the buyer from their “network” rather than just through marketing. Thus, having two broker “networks” might be better.
“Open listings” surface once in awhile. An open listing is made available to all brokers on the same basis. These are not a very viable option for the average seller, but sponsors (building owners) sometimes use them. Sponsors have deep relationships in the brokerage community and may be able to call 10 brokerages, be taken seriously, and say “if anyone in your office finds a buyer for my property on ABC Street, I’ll pay them a 3% commission, but it’s not going to be anyone’s exclusive.” Realistically, a normal seller cannot do this.