I see that most guys carry a 21 inch on their trailer. I am parttime and will stay that way due to having a full time job. I am looking at only 7 accounts next year and won't go pass 10. My questions are 1. Do I need a 21 inch on my trailer since I'm using a 36? 2. Can I get by with a residential 21 inch mower as a backup? I don't think I can justify spending $800 to $1000 on a commercial grade 21 inch with only 7 accounts. And I bought the service parts package for my 36 so I can quickly be up and running but hopefully won't be using it soon due to my 36 being new and having less than 5 hours on it going into next season. 3. Would a residential troybilt 21 with a honda engine work $239.00 since it will only see approx. less than an hour a week since the 36 will handle most everything. I know commercial is the way to go but I'm staying partime. Any advice would be appreciated.