the old debate: seo your own site vs other people's sites?

suppose there is someone that has a talent that could be turned into a business. let's say they know how to do plumbing work and the term "plumber [city]" gets a lot of searches.

The same person can either rank for "plumber [city]" or "seo company [city]"

he can't do both. It has to be one or the other.

Which choice would you suggest to him?

pros and cons:
with "plumber [city]" you own your own business but you still have to deal with people's shit.
with "seo company [city]" you have people on your ass all the time asking why they are not ranking after two weeks.

what do you think? what are the pros and cons?

Well first, what you are talking about is Local SEO. Not for the Lounge. This is a legit SEO topic.

Who are "you" in all of this? Obviously not the person that can do either/or, as that's pretty basic. FYI your own qualifications are a question. Also if you knew anything about SEO, you'd have some awareness of keyword search volume and how many searches plumber city gets vs. seo company city gets, and what the CPC is.

Because if you are the person who thinks you are going to rank either of those as #1 in any city with a population of more than 100, there's a problem right there and people that know things aren't going to waste their time with you. On the other hand, if you AREN'T that person, then why are you asking, what's your interest, etc...

"Plumber city" is a highly competitive kw in any city, and no one searches "seo company", so in terms of internet marketing you have to decide if you want a high-competition, high-profit keyword or a no-competition, questionable profit keyword.

Is the side just for lead generation? How much do plumbers pay for leads? What's a realistic conversion rate, what kind of volume of searches are you looking to get, or are YOU the plumber? If you are the plumber then go plumb something and hire a website developer and local SEO (they don't both have to be the same person) and YOU pay for the leads from your own website to incentivize the local SEO to maximize the number of leads coming in. Be fair and reward highly, keep the guy happy and he won't sell your leads to another plumber. You can pay based on volume, pay based on phone calls, pay based on the jobs you actually bid on or pay based on jobs you actually get. The farther down that process you pay, the more (obviously) you pay, but also the more metrics you have to track in order to make certain the arrangement is fair to both sides.

FWIW. Your question is vague and you'll have to provide more information before anyone can give you any kind of useful answer.