Pro-Gard, Techron or BG44K ... makes any sense?

hi,

I have around 50k ml on my Civic
does make any sense to use any cleaners as preventive maintains?
if yes - which one?

that what I found so far:

BG44K - $22. (Internet) for 10k ml
Techron - $6. (Wal-Mart) for 3k ml
Pro-Gard (with Techron) - $2.5 (Costco) for 1k ml

thanks for any comments
bb:confused: