Spend skill points in Jacob's and Evie's skill trees to level them up. As they level up new equipment and other tools will become available.

Level 1 to level 2: 4 Skill Points.
Level 2 to level 3: 4 Skill Points.
Level 3 to level 4: 8 Skill Points.
Level 4 to level 5: 10 Skill Points.
Level 5 to level 6: 10 Skill Points.
Level 6 to level 7: 10 Skill Points.
Level 7 to level 8: 15 Skill Points.
Level 8 to level 9: 15 Skill Points.
Level 9 to level 10: 18 Skill Points.