B737-800 Air carrier Captain reported low hydraulic pressure in cruise and during descent on both engines. Flight crew continued to destination and landed.

Narrative

On climbout of ZZZ at around FL 310 we received #2 engine low hydraulic pressure light. Ran QRH and notified Maintenance Control and Dispatch. Everything else was normal at that time. Maintenance Control notified Maintenance. Later in flight had Loss of System B. Ran QRH and notified Maintenance Control and Dispatch. We ran performance calculations and brake cooling for ZZZ1 XXL. Discussed situation of continuing to ZZZ1 with Dispatch. We were all in agreement of continuing to ZZZ1 (Dispatch; Maintenance Control; Supervisor and us). Notified ATC of our situation and [requested priority]. Notified Flight Attendants and Passengers of the situation. On descent we had another issue. The #1 engine low hydraulic pressure light came on. The A System pressure and quantity fluctuated a little and then stabilized at normal pressure and quantities. Ran QRH and notified Maintenance Control and Dispatch. Requested voice contact with Dispatch over ZZZ1 and discussed concerns with System A. Continued to ZZZ1; finished QRH for Loss of system B and landed on Runway XXL. Captain did the landing. Cleared the runway and taxied to remote area. Contacted ARFF while they monitored the aircraft. Ran brake cooling numbers again and had 18 minute hold out. Was notified of fluid coming out of number 2 engine. Shut number two engine down and was towed to Gate. Made required logbook writeups and discussed situation with ZZZ1 Maintenance. Then contacted Dispatch; Supervisor and Chief Pilot for debrief.