Note 9 Property, Plant and Equipment

TDS’ Property, plant and equipment in service and under construction, and related accumulated depreciation and amortization, as of December 31, 2015 and 2014 were as follows:

	Useful Lives
December 31,	(Years)	2015		2014
(Dollars in thousands)
Land	N/A	$	54,567	$	52,946
Buildings	5-40		506,486		480,028
Leasehold and land improvements	1-30		1,137,414		1,130,468
Cable and wire	15-35		1,688,606		1,628,782
Network and switching equipment	5-13		2,278,425		2,239,176
Cell site equipment	7-25		3,382,743		3,284,993
Office furniture and equipment	3-10		586,975		634,853
Other operating assets and equipment	3-12		205,132		204,625
System development	1-7		1,459,437		1,319,930
Work in process	N/A		220,276		218,243
			11,520,061		11,194,044
Accumulated depreciation and amortization			(7,755,584)		(7,347,919)
		$	3,764,477	$	3,846,125

Depreciation and amortization expense totaled $810.5 million, $797.6 million and $984.4 million in 2015, 2014 and 2013, respectively. In 2015, 2014 and 2013, (Gain) loss on asset disposals, net included charges of $22.2 million, $26.5 million and $30.8 million, respectively, related to disposals of assets, trade-ins of older assets for replacement assets and other retirements of assets from service in the normal course of business.