Budget, mostly. At the time I bought the place (end of 2009), I was earning about $28k from my day job and about $10k from my night job, getting taxed like crazy, and my wife was about to stop working to have our first child.
So i needed to look at the bottom of the market.
We only bought at the time because we could still use my wife's income for the application, and it didn't look like i'd be getting a pay rise for a few years as I wsa a trainee, leaving us renting for (forseeably) at least the next 5 years until our kid(s) went to school and my wife could get back to work or my income went up.
For the price, Clarkson ticked a number of boxes for my family: low maintenance (newish) building, bigger block (kids - 1 then, 2 now), walking distance to train, all our extended family (babysitters) are NOR, close to shops, parks & beaches.
Train from Clarkson to Perth Underground is just over 30 minutes. When I was in Marangaroo, I'd drive 15 minutes to the station and then train for 20. At least at Clarkson I was the first stop so I could get a seat.
As mentioned above, I had been working previously in deliveries for a Clarkson based store, gettting me alot of time on the streets and in the houses of the surrounding suburbs so I'd developed an idea of good areas and good streets. I intetionally avoided some areas , like near the aforementioned gang house. They were nice customers, (big purchase, cash, no haggling) but I had a feeling I didn't want them as neighbours.
As it turns out, I have done quite well salary-wise since then. I must be good at my job or something. And although I am looking for a bigger place, I'm still leaning towards staying in Clarkson, also considering Merriwa, Ridgewood and Mindarie (if I can snag a bargain). I wouldn't mind getting into the Somerley estate west of Connoly drive, which I am barely outside of now. (although If you check out the thread I started a couple of days ago, you'll see I'm not currently living in my Clarkson house)