Usage: analogically simplified (类推简体) vs. original characters
The latest standard is 《通用规范汉字表》 (List of Commonly Used Standard Chinese Characters) formally released in 2013. In practice, 226 analogically simplified characters are identified as 规范字 by the authority; other traditional characters that are not included in 通用规范汉字表 should not be analogically simplified and should keep their original forms.

Related information is quoted as follows:


What the standard says


  《通用规范汉字表》p. 9, 说明
  
  六、本表对社会上出现的在《简化字总表》和《现代汉语通用字表》之外的类推简化字进行了严格甄别，仅收录了符合本表收字原则且已在社会语言生活中广泛使用的“闫、(钅仑, U+2CB2D in CJK EXT-E)、(兆页, U+2B5AF in CJK EXT-C)”等226个简化字。
  
  
    This list has strictly examined and assessed the analogically simplified characters that apprear in society but are excluded in 《简化字总表》 (Complete List of Simplified Characters) or 《现代汉语通用字表》 (List of Commonly Used Modern Chinese Characters), and includes only 226 analogically simplified characters, such as 闫, (钅仑, U+2CB2D in CJK EXT-E), and (兆页, U+2B5AF in CJK EXT-C), which are consistent with the inclusion principle of the List and have been widely used in social life.
  

How the authority interprets the regulation for analogically simplified characters. It's a controversial topic in the academic circle (FYI, read these two articles 1 &amp; 2), but the opinion in 《〈通用规范汉字表〉解读》 should be considered as the current practical standard – Keep the traditional characters unchanged if they are not in 通用规范汉字表. 


  原征求意见稿说明中曾有“根据国务院1986年'今后对汉字的简化应持谨慎态度，使汉字的形体在一个时期内保持相对稳定'的指示精神，本字表以外的字，不再类推简化。”此字句于正式版中消失，即字表本身没有提及字表以外的汉字如何使用[11]。但是《〈通用规范汉字表〉解读》中提到，无限制的类推「实际上使汉字的总体系统繁化甚至混乱……违背了辞书存储汉字的历史真实性原则，拉大了汉字应用的古今差异和两岸差异」，并说明「……收录了少数已经被社会所习用，并符合《简化字总表》规定的类推简化字。今后表外字不再类推简化。」 [12]
  
  
    The explanation in the former draft for soliciting opinions once said "According to the instructions of the State Council in 1986 From now on further simplification of Chinese characters should be prudent. Let the forms of Chinese characters be relatively stable in a period., characters excluded from this list will not be analogically simplified." However, this sentence disappears in the formal version – It indicates the List itself does not mention how to use the characters that are not included within the List.[11] Yet, 《〈通用规范汉字表〉解读》 (Interpretation of the List of Commonly Used Standard Chinese Characters) mentions, an unlimitedly analogical simplification "actually makes the whole system of Chinese characters complicated and even chaotic ... which violates 'the principle that dictionaries should reflect the historical genuineness of the usage of Chinese characters', and increases the divergences between ancient and modern Chinese and between Mainland and Taiwan", and further says "... (the List) now includes a few analogically simplified characters that are consistent with the principle of the List and have been widely used in social life. From now on, characters that are not included in the List will not be analogically simplified."
  
  
  [11] 《通用规范汉字表》以外的字应准许类推简化. 光明网《光明日报》. 2013-12-14.
  
  [12] 教育部语言文字信息管理司组 编，王宁 主编. 3.3 《通用规范汉字表》对待类推简化的态度. 《〈通用规范汉字表〉解读》. 商務印書館. ISBN 9787100100939 （中文（中国大陆）‎）.

These 226 analogically simplified characters are


  



PS: The voices from the academia against "characters that are not included in the List should not be analogically simplified" are strong. In my opinion, both sides have got a point: For the positive side, it largely simplifies the Unicode encoding for Chinese characters and is very pragmatic – just consider the difficulty and trouble when people try to input rare Chinese characters on a computer (some analogically simplified characters don't even exist in Unicode!); For the opposing side, it does make some paragraphs extremely ugly when the simplified are mixed with the traditional – in the aesthetic and purist view point.