If you are not using the provided change addresses so you can redirect the change to a different wallet, perhaps a different address type to confuse transaction heuristics and blockchain analysis, or perhaps to deposit to an account at a service, then that's a great idea and good use of your change.

If, however, you are doing as NeuroticFish suspects and just sending the change back to the same address it came from, then can I ask why you are doing that? It achieves absolutely nothing beneficial, it does not make future transactions any smaller, it does not save you on fees, but it does compromise your privacy and the privacy of other people you are transacting with (and potentially even your security in rare cases).

The size of the Bitcoin blockchain is increasing by linear progression (about 100GB every two years), while technological advancements in the IT industry continue to grow exponentially. For example, a decade ago, most personal computers had disks drives with a capacity of 320GB or 500GB. Nowadays, most new PCs come with drives that hold 2TB or even 4TB. In fact, storage capacity is doubling every few years and data transfer speeds are increasing even more rapidly.


https://www.statista.com/statistics/647523/worldwide-bitcoin-blockchain-size/

So, unless the rate at which new blocks are generated dramatically changes, there is no concern that blockchain data will surpass the limits of technological advancement in the foreseeable future.

Based on their decisions they might as well just get on with it and ban Bitcoin every week.

As for Tor, can they even actually use it? As using VPNs are illegal as far as I know.

That’s the same thing with every country, if you’re using VPN to access a website that the government has declared illegal then it is illegal. I don’t think VPN itself is what is illegal in China, it is what you’re using it for; if you use it for something illegal, then it is illegal.

I know this is not a perfect example but isn't it the same country blocked lots of other popular websites?

I haven't seen such websites "collapse" because chain blocked them

Just to show you how China is ridiculously full of censorship, check out how many websites and apps they have blocked so far  

01.    Gmail
02.    Dropbox
03.    Google Apps (Drive, Docs, Calendar, Maps etc.)
04.    Microsoft OneDrive
05.    Slack
06.    Google Play (i.e. no downloading Android apps)
07.    Hootsuite

08.    Facebook
09.    Instagram
10.    Twitter
11.    Snapchat
12.    Pinterest
13.     Quora
14.    Tumblr
15.    Reddit
16.    AO3

17.    YouTube
18.    DailyMotion
19.    Vimeo
20.    Twitch
21.    Periscope
22.    Pandora
23.    Spotify
24.    Soundcloud

25.    New York Times
26.    BBC
27.    Financial Times
29.    Wall Street Journal
30.    Reuters
31.    CNN
32.    TIME

33.    Google (text and voice)
34.    Amazon (Alexa)
35.    Wikipedia
36.    DuckDuckGo

37.    WhatsApp
38.    Facebook Messenger
39.    Telegram
40.    Line
41.    Signal
42.    KaKao Talk (Korean)

43.    Medium
44.    Blogspot

45.   Skype (although it sometimes works, it’s not reliable)
46.   Google Hangouts
47.   Viber

48.   Porn websites
49.   VPN websites
50.   Politically sensitive sites

So it's just another day in China.

I didn't know about it. I thought China wasn't taking the global deals to decrease co2 emissions seriously.
But don't you think even chinese citizens not caring about decentralization it's still a risk for the government to have a decentralized currency becoming more popular each new day? In government's point of view, investors' money could be going to the national industry instead of a global currency which they have no control over it.