My wife was told to do the taqlid of Syed Sistani being told he is easy, but never really researched his rulings or never really follows him but after marriage I told her to do taqlid and I her husband am in the taqlid of Syed Khamenai, can she change her taqlid to syed khamenai given she never really followed syed Sistani in the first place

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Taqleed is based on following the most knowledgeable mujtahid, not for being easy.
It is not necessary that both couple follow the same mujtahid.