Though legacy Time Warner Cable systems often have had the same channel map across most of their service territory since the early 2010s (with standard definition networks from channels 1-999 and HD networks on channels 1001 and above and certain channel groups per group of 100 channels), legacy Charter systems often do not, and in both cases, channel maps have changed as networks have been added and subtracted over the years and due to regional or local differences emphasizing certain networks over others; often, pre-digital cable systems have retained the same channel map below channel 100 since the mid-90s to avert customer complaints about changes as channel drift sets in across individual networks. Currently, the only universal channel numbers across all legacy Time Warner and Charter systems are channel 1 for the local Spectrum News channel, channel 999 for video on demand access, and channel 2495 to add new premium services.