If you leave the scheme before your normal retirement age your benefits will be become deferred and will increase each year in line with the cost of living.
If you subsequently re-join the scheme at a later date and aggregate your periods of scheme membership, provided you do not have a break in membership of more than 5 years from any public service pension scheme (e.g. the Teachers, NHS, Civil Service Schemes), any pre 1 April 2014 LGPS benefits will be calculated on your Final Pay when you eventually leave the scheme or retire.
If any break in membership from public service pension schemes is more than 5 years, and you decided to aggregate periods of LGPS membership, any pre 1 April 2014 benefits would not be covered by the Final Pay protection but would instead be converted to a CARE benefit in the new scheme.