I bought my '03 T4R used (second owner), and in the service history it indicates "lamp" maintenance at 53,000 kms - but I am not sure if this was for the front turn signal bulbs or not as it was done by the first owner.
I did replace the front driver's side turn signal bulb (and it operates as the daytime running light here in Canada) at 118,000 kms.
all the time. I have had to replace mine at least 4 times in the last two years. Determined they keep getting wet and shorting out. Used some dialectic grease back in September on the last set, so hopefully these will last.
Replaced my first one on my '05 (which doubles as running light) on the drivers side in May (56K miles). It blew again in October, then that one blew a couple of days later and the socket wouldn't light a new bulb. I replaced the socket and all has been well since.