I bought a $139 mower at HD circa 1997. Spent another $40 or so on steel BB wheels. The motor finally blew last year, so the new owner re-engined it and kept going. Mower was used twice weekly, every month, during that time.
One of my neighbors owns a landscape business. Years ago he bought 4 Poulan/GCV160 powered push mowers 4/$500 (best of my reccolection)from some hardware store going out of business. He just can't pass up a deal. Used 2, sold 1, still has one in the box.
Of the two he used in his business, the plastic wheels lasted about a month. He bought some steel/ballbearing replacements from Granger and hasn't looked back. He went with larger diameter wheels as well to get more cutting height on that thick dark green grass landscapers use now.