can i get by with a residential mower?

I mowed yards from 15-18 yrs old an made good money, my dad got a great deal on an 06 cc tank m60 $4000 with like 50hrs an we split the cost 50/50.. I was to keep our yard looking sharp 24/7. I did everything from getting the customers to sharpening the blades an buyin weedeater string to getting the cash he never even knew where I was. (just giving yal some background so were on the same page) I then stopped mowing an got a job at a powerplant but recently quit because I was tired of it lol I got a good 30hr a week job but want to start mowing on the side again...I already have about 5 good yards that iv got in the last couple weeks an been using the same m60 tank...its still a good mower but I need my own. the yards r all in a huge gated community and really nice and that's the only place I plan to mow...old ppl with money who like high quality work an don't have to worry about me stealing or anything like that, most get me set up with there bank and forget about the yard, I keep it nice. I know this is a small story but just bare with me. I grease an wash my mower every weekend and change the oil regular etc. my mower will be very well kept. I only want to do this on the side and don't want to have 6-9k invested on a mower, I already have a good weedeater an blower for my own yard...and a good 5x8 trailer for my 4wheeler, right now im using my dads 7x16. if I get 20 great yards at 1hr per yard, 10hrs a week for 25 weeks a yr, 250hrs total, will a 48" residential 4000$ mower last 2 years being babied? it will never have to cut thick grass or be strained. thanks