How good is your (legal) English?
For example, do you know the legal difference between "will", "shall" and "must"? Or, the difference between "employee", "subcontractor" and "worker"? Or the difference between "bankruptcy", "insolvency" and an "act of bankruptcy"?
What are you going to put in your dispute resolution clause? Do you prefer mediation, arbitration or litigation? Will it be a one size fits all or will it be escalating?
What happens if one of you dies? Or emigrates? Or divorces? Or is convicted of a crime? A financial crime? A violent crime? A sexual crime? Or what if such is just alleged but not proven?
What happens if the company ceases to exist? Or is sued? Or is acquired by someone else? Or by one of you?
Who is responsible for insuring the subject matter of the contract (if anyone)? To what value? If the person who should doesn't can the other person effect the insurance and claim the premium as a debt due and payable?
Not all of these will be relevant to your contract.
How familiar are you with this sort of contract? Is this something you do all the time or is this a one off? For example, I am happy to enter a construction contract without legal advice because that's my business and has been for many years - I know my risks and how to manage them, inside and outside the contract. However, when I set up shareholder's agreements, wills and business continuation insurance with my partners, we went to a lawyer.
What is your relationship with the other person i.e. how much do you know and trust them?
If the contract is not very important (which is something that varies with the participants, for some people a million dollar contract is not important for others a $5 one is), so that if, by screwing up, you are OK if you lose everything you've staked then write it yourself.
Alternatively, if the contract is vitally important to you and your heirs and assignees unto the 6th generation, I'd get a lawyer to write it - its pretty cheap insurance.
How long the contract lasts will be a factor in this - a contract that exposes you to risk for 3 months is different than one that does so for 25 years.
Basically, its a risk reward calculation.
Contracts only matter when relationships break down.
If you reach for the contract then you can expect that the other party will be playing for keeps and that contract is your only defense against the worst they can do. If you are happy with your skills in mitigating against a cashed-up opponent who wants to see you go down no matter the cost then draft it yourself.