Do I need to use a PhiX DNA spike-in during the sequencing SMART-Seq Stranded cDNA libraries?

Do I need to use a PhiX DNA spike-in during the sequencing SMART-Seq Stranded cDNA libraries?

Illumina recommends the systematic inclusion of ~1% PhiX DNA to help assess run performance and troubleshooting. If performing paired-end sequencing on two-channel Illumina sequencer consider adding 5-10% PhiX.

SMART-Seq Stranded kit