KTickler,
I see you got the usual assortment of "No, Never, & No Way". These probably come mostly from the youngsters in our community.
Consider the parallel question: Do you think you could ever get tired of sex?
For many of us, tickling and sex are intertwined in many interesting and complex ways. I can't speak for everyone, but the only time I have little interest in sex is immediately after being gratified. With tickling it is much the same, in that it depends on how long I might need to 'regenerate'.
Body chemistry is a curious thing, and age takes its toll whether we like it or not. So do other factors, such as stress, mood swings, diet, and overall fitness. However, as individuals, we all have different rates of aging, and the interest levels rise and fall accordingly. Years ago, I would have said "never" to these questions, just as many others have done. Now I know this was wishful thinking, so all we older folks can hope for is that the desires only fade gradually.