When PCR duplicates should be removed?

DNA-seq (WGS, WES)	ONLY IN CASE OF PAIRED-END RUNS
BS-seq (WGBS, RRBS)	ONLY IN CASE OF PAIRED-END RUNS
WTS RNA-seq	ONLY IN CASE OF PAIRED-END RUNS
mRNA-seq	ONLY IN CASE OF PAIRED-END RUNS
single-cell RNA-seq	NEVER
small RNA-seq	NEVER
ChIP-seq	NEVER
Amplicon sequencing	NEVER