The likelihood of recurrence depends on the size of the primary tumor and the extent of spread beyond the kidney. You say you had two stage I tumors. Were they in the same kidney? With the most common kidney cancer, clear cell renal cell carcinoma, it is rare that one kidney develops more than one tumor, and also rare for it to spread to a previously unaffectedtumor. Tumors in both kidneys sometimes indicates a genetic cause, and perhaps a different type of kidney cancer. Kidney cancer is a bad actor; it can come back many years after tumors are removed. You should have periodic checks for the rest of your life, because when kidney cancer comes back after a long disease free interval, it can come back as one or two small metastatic tumors which can be removed surgically if found when they are still small. With stage I tumors the likelihood of recurrence is small. My sister has gone 10 1/2 years without a recurrence.
There is an email support list specific to kidney cancer. See
http://cancerguide.org/kofaq/.