<font color='black' size='2' face='Arial, Helvetica, sans-serif'>I suspect there's no one hard and fast number for this as how it's used and maintained would be a big factor in the condition. Another good reason to keep a usage log. <br>
<br>
<div style="font-family:arial,helvetica;font-size:10pt;color:black">Kristi R-C <!-- end of AOLMsgPart_0_b1bb6b97-071e-40cd-8fc3-d5713c17f4f8 -->
</div>
</font>