Toyota Repair: upcoming repairs

Question
Hi Ted,
I have a 1998 toyota camry 6 cyl with 149,000 miles on it. I drive about 6,000 miles per year.  The transmission was serviced 2 years ago @ 132,929 miles.  How often do I need to have it serviced?
Spark plugs last replaced at 102,000 miles.  Do I need new ones now?  Mechanic says I have value cover leaks (front and back) and that I should put in new spark plugs if I replace valve cover gaskets.  What do you think?

Answer
hello, the transmission should be serviced every 60K miles about every three years, the spark plugs are platinum tipped and they are replaced at 60K as well. Valve cover leaks are common on this engine so no surprise there and definitely replace the spark plugs when the gaskets are replaced. The timing belt should be replaced at 90K miles