I just replaced my coach (house) batteries. I had three Trojan 31XHS with 130 AH rating at 20 Hours each for a total of 390 amp hours.http://www.trojanbattery.com/products/31XHS12V.aspx
The new batteries are Trojan 30XHS with the same exact same rating.http://www.trojanbattery.com/products/30XHS12V.aspx
The old batteries were 7 years and 9 months old and cost $100.00 each +tax.
The new batteries cost $150.00 each +tax; a 50 % increase in ~8 years.
The old batteries cost me $3.22/month, not too bad. In that time period, probably about 600 to 700 camping days mostly off the grid.