Is the blessing of Shehechiyanu optional or obligatory?
The saying of the blessing of Shehechiyanu [over new fruits and joyous tidings] is not obligatory and was instituted by the Sages as an optional blessing that one is allowed to say if he so feels, in those instances permitted by the Sages. Thus, many are accustomed to being lenient and not to say the blessing of Shehechiyanu [over joyous occasions]. Practically, however, in those instances where it is permitted to be said, one is not to be lenient and avoid saying it. [Furthermore, regarding new fruits, the custom of Israel is to be particular to recite it, and it is hence viewed similar to an obligation.]
 Rama 223:1; Admur Luach Birchas Hanehnin 11:31 [omitted from Seder 12 thus implying that it is obligatory]; M”A 223:3; 225:6; Eiruvin 40b; Shiltei Hagiborim Eiruvin 40b; Olas Tamid 223:1; Elya Raba 223:2 and 225:6; Soles Belula 223:2; Chesed Lealafim 223:4; M”B 223:7; Piskeiy Teshuvos 225:1
 See Eiruvin ibid; Elya Raba 223:6 and 22:2; Aruch Hashulchan 225:1
 Admur ibid; Rama ibid; Rashba 1:245
 Luach ibid [Seder ibid completely omits the opinion who rules that Shehechiyanu is optional, thus implying that he rules that it is obligatory]; Elya Raba 223:2; 225:6; Shiyurei Bracha 223:2
 Aruch Hashulchan 225:1; See Elya Raba 225:6, brought in M”B 225:9; Hagahos Semak 151 that it is an obligation