I replaced my stock (24 spoke) wheels on my Giant TCX 1 after breaking a spoke on the rear wheel. It probably wasn't tensioned properly. I got a set of wheels with 32 spokes. After my first ride, I trued both wheels and here's the important part, checked the tension. For us big folk, spoke tension is the most important. I ended up increasing the tension on quite a few spokes that were low (rear wheel especially). Its the low tension ones that break.
I retensioned/trued one additional time after 3 more rides and I haven't had to mess with them since. I think I have about 250 miles on those wheels since the last time I had to true them. I due check once in awhile to make sure.
I'd recommend getting the tools and doing it yourself. I think someone said it here before "never loosen a spoke". Your wheels should stay true after that.
John