Get a quote for mowing your lawn from a landscaper. Then figure out the payback. If the mower lasts longer than the number of months you’d pay a landscaper, not an idiot. Otherwise...Idiot.
I've done the math a 100 times. I just can not cost justify mowing my own lawn. Heck, just for fun lets do it again. Let's say a decent mower is 5K. You can get a half acre mowed for 40 bucks in Houston as I recall. Say 30 cuts a year for 1200 bucks annually. To do it yourself, you've got a 4.1 year payback just on the mower. Then add in fuel, oil, maintenance. Let's call that 250 per year. Let's say you can mow the whole thing and do the trim work in 1.5 hours. If you value your time at 25 dollars and hour, that's $1125. Add in the fuel and maintenance cost and you are actually worse off mowing your own lawn.
In my mind the only time it make sense to mow your own lawn is:
1. You are in an area where the cost to outsource it is extremely high
2. You have an enormous lawn (in which case you should buy your own equipment and hire a neighbor kid)
3. You have some kind of a Napoleon complex where you need to have the best looking yard in the neighborhood
4. You put close to zero value on your time (which in my opinion, should be viewed as your single most expensive asset)
Don't forget to lather up to avoid skin cancer each time you mow as well. See my other post on how you'll die.