9:3:1
If your a DX 8:8:1
Like Brandon said before, there really is no service limit, if your compression is uniform....your engine is good. As the miles are put on your motor, all the cylinder should lose compression evenly. It would take years and a lot of miles, if you change your oil regulary.
Whatever Jiffy lube instilled in you is wrong, you dont need an engine flush if you use the good oil and change it on time.
Engine flushes will ruin your car, it can clog oil galleries. Its not part of Toyota, Honda or any other manufactures specs. And it will VOID your warranty.
I had a nissan hardbody with 365k and I never did an engine flush, I bought it from the original owner who always changed his oil on time or before it was due. I took the head off to do a head gasket and that engine was clean enough to eat off.