Do take note the Touch n' Go for your IC has validity of 10 years, after which you need to replace a new IC.

a little less known hack:
after your IC TnG expiry, u can actually bring it to any LRT/MRT counter & ask them to extend validity for another 3 years.
they will a bit reluctant & discourage u to do so, saying it may be unusable eben after extension.
ignore it & insist on extension. they r actually require to do it.
the discouragement is just empty threat so they can sell more tng card.
it's perfectly fine to extent.

after that 3 years extension, then only it's really expire & u can no longer use it unless u change new ic.