The sick leave can't be used (cashed in) for achieving retirement eligibility, but it will be added towards your (time served) pension valued at the rate of a day for a day.
Now keeping that in mind lets say a days pay (sick leave) is equal to $300 dollars, so 5 sick days (a week) is worth $1500 dollars. Now if you have 100 sick days (20 weeks) its worth to be used is $30,000 dollars.
Now look at using it to add time to your retirement at a rate of 1 Sick Day = 1 Day towards time served. That would give you 20 weeks (39% of a year) additional time towards your retirement. So roughly 40% of a year or (.004) towards your pension. Each full year counts as 1% or .01 of your high 3. So your multiplier is 30.4% or (.304).
Using the data above $300 a day equals a working salary of $78,000 per year. So your high 3 would be about $75,000 maybe. Doing the math .004% of $75K is $300. per year towards your pension.
For example lets say you have 30 years at a high 3 of $75k your Pension would be Approx. $22,500 per year without Sick Time added to it or $22800 with it included.
$22,500 / 12 = $1875.00 per/mo.
$22,800 / 12 = $1900.00 per/mo.
a $25.00 per/mo. difference.
Based on these calculations, that $30k dollars you could have received by using the Sick Days before retirement, it will take you 100 years in retirement for you to break even!
$300 x 100 = $30,000 dollars.