How common is this in software programming job contracts for either freelance or full-time work, and does this clause usually depend on the level of compensation for the job?
Assuming you mean "While you're working for us, you won't work for anyone else" as opposed to a non-compete, which is another kettle of fish entirely:
Full-time work: fairly common. It is as negotiable as anything else in the employment contract, which is to say highly variable depending on the employer and locality. Anecdata: a Japanese megacorp, not generally known for huge amounts of flexibility in employment relationships, was willing to bend on this as long as the moonlighting wasn't another full-time position as an engineer.
Freelance: it is heavily again a client's legal interests to ask you for exclusivity (it's virtually dispositive of there existing an employment relationship with you and every other freelancer/consultant they have on the same paper, opening your client up to ruinous fines for failing to remit employment taxes) and against your interests for you to grant it. I'd generally take this as a sign of organizational immaturity. Your competent legal advisor will strongly, strongly advise you to not grant your clients exclusivity -- even if you're fully committed during the course of engagements you'll typically be shepherding other gigs through the pipeline simultaneously and the risk of them running afoul of the clause will typically be unacceptable.
does this clause usually depend on the level of compensation for the job?
I know $30k a year programming jobs that wanted exclusivity and $30k a week programming jobs which wouldn't dream of asking for it, so, broad strokes, not really.
In one case, I just ignored it. In fact, the company was actually buying services from my side business, knowingly, while I was working there. Pretty sure the "executives" who drafted these agreements never even read them.
In a second case, I brought it up during negotiations. They amended my offer letter to allow for my existing clients, but no new clients.
In a third case, it was not mentioned. However, I was telling a coworker about my outside activities and he ratted me out to a VP. I was then told I wasn't allowed to do any outside work. I pretended I cared, ignored him, and kept on doing what I was doing. No long term consequences were had.
Full-time work: fairly common. It is as negotiable as anything else in the employment contract, which is to say highly variable depending on the employer and locality. Anecdata: a Japanese megacorp, not generally known for huge amounts of flexibility in employment relationships, was willing to bend on this as long as the moonlighting wasn't another full-time position as an engineer.
Freelance: it is heavily again a client's legal interests to ask you for exclusivity (it's virtually dispositive of there existing an employment relationship with you and every other freelancer/consultant they have on the same paper, opening your client up to ruinous fines for failing to remit employment taxes) and against your interests for you to grant it. I'd generally take this as a sign of organizational immaturity. Your competent legal advisor will strongly, strongly advise you to not grant your clients exclusivity -- even if you're fully committed during the course of engagements you'll typically be shepherding other gigs through the pipeline simultaneously and the risk of them running afoul of the clause will typically be unacceptable.
does this clause usually depend on the level of compensation for the job?
I know $30k a year programming jobs that wanted exclusivity and $30k a week programming jobs which wouldn't dream of asking for it, so, broad strokes, not really.