It's been 5 months since the chem clean. I practice about 1/2 to 1 hour a day. About once a week (more if I'm performing) I take the valves out, clean, and re-oil. I've not had a sticky valve since the chem clean. The first time I have a sticky valve I will have it chem cleaned. Where I live, the chem clean costs $60. If I have to have it done twice a year, it will be well worth the money spent.
KKORO