SNR and Repetition Time
What effect does increasing TR have? There would be more time for longitudinal recovery of the net magnetisation, meaning more signal is available to us in the next TR, for the next line of k-space. So an increase in SNR occurs according to the T1 recovery curve.
Tradeoffs: allows an increase in coverage (more slices), less T1 weighting, more proton density and T2 weighting, increases scan time.