IP address changes

[#1]

Hi my IP address seems to be changing every few days, hardly a complaint but I was wondering if there's a reason why this would happen.  It's gone from range 87 xx xx xx to 146 xx xx xx and now it's 213.162 xx xx seem really odd ranges? Are Plusnet working on the systems or could my hardware be iffy?
Thanks

[#2]

That's perfectly normal - it probably changes every time your line resyncs.
If you want a static IP, you can get one for a £5 one-off fee.

[#3]

Yep, each time you disconnect/reconnect you'll get a new IP address. Nothing to worry about.