Average 8-15 years for the sign, and 5-7 years for the transformer. The transformer can be replaced. The neon can be recharged.

depending on the length of neon.. a large sign

15Kv at 60 Ma is common 1Kva

No. The neon sign is fed by a step-up transformer. Primary side 120V, secondary side 7500V. If you applied 240 to the primary side you would get 15000 volts on the neon tube. A flash over and then nothing. If you can find a transformer from 120V to 240V or 240V to 120V then you are good to go. Connect 240V to 240V side and you will get 120V out the other, connect the 120V side to the neon sign and you should have light. Transformer should be at least 100va. This will give you an output of .83 amps at 120V

What you will need is a 240 to 120 step down transformer. An adapter might work but it depends on what the current draw of the neon sign is at 120 volts.

A common gas found in a neon sign is neon, hence the name.