Finally, new brokers should dip into their personal connections as a means to get off the ground.
2. Cash
The delay in cash coming in means new broker-business owners must consider their entire cash position, including the bills that need paying.
"You've got to factor in that the average time for a mortgage to complete and pay out is going to be about three to four months," says Barnett.
This means little to no income for a few months, apart from perhaps protection fees, although brokers have the option to charge broker fees should they wish to.
"You don't want to be in a position where you're having to force mortgage cases through because you need the cash. It's non-compliant, it's unsafe, it's not the right thing for your clients," he says.
He says the best way to assess one's cash position is to do a cashflow forecast, accompanied by a 'what if' analysis.
"Always consider the worst, I would say, and just consider what options you have there, I think that's really important."
3 & 4. Confidence and Commitment
New brokers should be confident in themselves and their service.
It's worth remembering that just because they have their own name above the door doesn't mean everything changes, they are still doing the same work of advising clients, says Barnett.
The other thing to consider is that while it will be hard work it can be rewarding at the same time, he adds.
"The job can be great. But it's important to realise that you have that work-life balance but it is going to be hard work."
Brokers should consider their "non-negotiables", or unique selling points - the things they do differently to others and will not budge on.
These could centre around client service, or certain principles, or offering a WhatsApp service between certain hours of the day no matter what.
"You've got to factor in here that there isn't gonna be sick pay, and there's no holidays. However, you are going to be your own boss, so you decide when you want to work," says Barnett.
"The most important thing is a business plan," he adds. "You've got to plan your business down to the really granular detail to ensure that you are considering all of your options."
He suggests a technique called a pre-mortem, whereby the business owner looks 18 months down the line and imagines the project has failed. They then work back to figure out why it has failed.
These scenarios can then be considered in the business plan and mitigated against.
5. Correct time
Finally, brokers wishing to start their own business should ask themselves whether now is the right time. And if not now, when?