Validity of Visitor Visa

[ndinakar]

My parents are planning to go for visitor visa next month. But they dont intend to come visit me right away. Theoretically, if they get a 10yr multiple entry visa, is there any limit or earliest date before which they have to visit me or they can pretty much come anytime during the 10 yr period? Once they have the visa, does change in status of either the sponsorer or their status as in them getting retired nullify the visa or is the visa good regardless?

Thank you for your advice.

[peace]

A change in status of sponsor and the applicants is
unavoidable during a 10 yr period and it is assumed considered when a 10 yr visa is granted.

And they can travel anytime during the validity period; no restrictions after it is granted unless there is an annotation
on the visa making restrictions.

[ndinakar]

Great. Thanks "peace".