Putting all your financial eggs in one basket is never such a great idea, which is why folks rich enough to buy shares tend to buy them in lots of different companies. Take tips on money management from the rich, they know what they're about!
My household has a total of 4 different income streams, so hopefully if any of them go pear-shaped we can still afford to pay the bills by working harder at the others.
Our main business is a small taxi firm, but like everything around here it's very seasonal. However, at the very least, it pays for us to have transport & gets us out to meet folks... I could VERY easily turn into a total recluse without the excuse to go out & shovel drunks up off the pavement every week end! It also means we know everyone, so if we need an electrician or someone to fix the computer or mend a leaky roof then we really KNOW them, where they live & how pissed they get at the week end. :-) My Etsy shop generally pays the mortgage most months & is a reasonably steady income, ie, variable but not seasonal. My better half is an environmental scientist by education, but only works freelance & occasionally these days, so what he makes on that is a bonus. He also works part-time looking after swimming pools locally (both private ones, & one attched to holiday letting businesses) His income from that is annualised, but the work is seasonal. Altogether, it means we can live in a place that others can only aspire to visit on holiday or retire to, we can choose to spend the day in the garden if we feel like it, & offices are something that happen to other people. We'll never be rich, we rarely eat out & never go on holiday, we don't even have passports... but where could we ever go that would be better than here?
So Damien, don't measure yourself by other people, EVER. Build a life that you like & live it. Be unconventional. Be yourself. Be happy.
And every so often, stick your head the higher side of Exeter to remind yourself why you live here & not there. Spare a thought for all those office-wallahs baking in their cars on their daily commute to spend a glorious day like today in windowless air-conditioning while you're sitting in the sun in your shorts to earn a living... or in my case, often swimming in someone else's swimming pool! At the very least, you can look out of the window onto green trees & hve coffee whenever you like. Ask yourself if you'd swap with them & go to live & work in some soulless grey concrete desert, just to have more money. I wouldn't.
So no, taking a part-time job is not an indication of failure, but a sign that you're building your own personalised lifestyle.
Good luck & have fun!