And the answer is to explore, select, and play.  There is no unique solution for all, instead, it is recommended to assess yourself, your options and objectives to decide the right string and tension.

Right string and tension depend on the skill level and the type of the player. Before the selection of string type and tension, we should know about the sweet spot. 

Sweet spot

A sweet spot on a racquet is an area which gives the most power, analogous to the ‘middle of the bat’ in cricket.

At low tension (18lb-23lb), the sweet spot is bigger, which means that a player can generate power even if the shot was slightly mishit.

At high tension (24lb-30lb), the sweet spot is smaller and the power generated is lesser because the strings are tight for the trampoline effect to take place. Control over the shuttle increases because the strings are flatter which is suitable for advanced players who can generate enough power, have excellent basic techniques and need accuracy in all shots.

Recreational/club players can choose a string tension based on the type of game you want to play. If you are lacking in power, you can go for a low tension string that increases the power in each shot. If power and control are both important to you, use a middle level tension that gives the best of both worlds. Do not let your ‘ego’ affect this decision. Plenty of recreational players string their racquets beyond the recommended racquet tension because that is what the professionals do.

Selection of Badminton Racket String Type

Lots of badminton racket strings are available in markets which can create troubles for the badminton players in the selection of their racket strings. Make a purchase of your badminton racket string depending upon your style, level, and play. Let us discuss the factors which influence the string selection.

Resilience/Durability: If you need more lifetime of the string, thicker badminton strings are needed. . This will allow the players to take advantage of additional durability. Badminton Strings such as the Yonex BG 65 string are ideal for all-rounder badminton players. Yonex string package has color code yellow to specify the "DURABILITY".

Repulsion: If both durability & repulsion is the choice, then choose thinner strings lesser than 0.70 mm. This variety of ultra-thin badminton strings offer an extraordinary repulsion along with tough strokes. Yonex string package has a color code blue to specify the "REPULSION".

Control & Power: If both power & control are your choice, then opt for thinner badminton racket strings, let you play controlled strokes easily. Moreover, ultra-thin badminton strings offer improved control, powerful smashes, and higher durability.  Yonex string package has a color code green to specify the "CONTROL" and pink to specify "HITTING SOUND".

1. Skill Level: Low tension (18lbs to 22lbs) is suitable for  beginners because lower tension offers a widened sweet-spot area on the racquet. Medium tension (24lbs to 26 lbs) is fit for intermediate players that provides a balance among shot accuracy, power generation, repulsion and sweet-spot region. High tension (26lbs to 30 lbs) is suitable for professional players who like to play crisp/accurate shots. 
2. String thickness: Higher the thickness of string, lower string tension is suggested. For example, thicker 0.7 mm Yonex BG 65 needs low 26 lbs tension, whereas thinner 0.65 mm Yonex BG 66 Ultimax (thin string) can perform better with higher 28 lbs tension. Higher thickness strings are durable.
3. String life: Racquets strung at lower tensions are more durable compared to higher tensions. Thinner strings usually break faster than thicker strings strung at the same tension.
4. Racquet compatibility: Refer the racquet specifications before you string as maximum tension and string compatibility.

String thickness and tension Relationship and their characteristics