Does sim cards need replacing after certain number of years? Do they get old and worn out?

Old sims becomes less effective?

Airtel does kick you out of network after a number of years. Personal experience, had to pay 118 for new sim even when old was in phone for last 3-4yrs… I had received old one as replacement for 3g to 4g network…..

Old SIM decades back didn’t had 4G support so most operators had to ask customers to upgrade SIM
In past operators have also upgraded SIM card with better memory (i.e 64K to 128K or so)

All depends on when have you taken the SIM…if it supports 4G ideally you should not have any issue because of SIM

For shift from 3g to 4g? Yes you need to change.
Also the newer sims have new technology. And better memory. For eg Try adding a long name in your old sim vs new sim(character limitations)
Usually sim pads get reduced/wear off if you are chindhi user like me who keeps on interchanging sims for any offer.
You won’t get super super high signal boost just because you got new sim.

i dont think that matters ,
i have bsnl 5 years old sim and it still works best even it is damaged and scratched

i used tata docomo sim for 6 years… finally Airtel delivered 4G sim at doorstep without any charge.

Using tata docomo sim from 2009 in nokia 101. always active but just for sms. Airtel keep sendind msg to change it to 4g, waiting till date it loses connection as happened with other airtel sims.

2 of my Airtel nos. are not being detected in any device be it a feature phone or smartphone. Only a few years old. Originally Tata Docomo nos. upgraded to Airtel 4G after the merger. Last worked in Jan w/o any issue. Seems fishy?