Characteristics to know when searching for an app:
Price
It is totally free
You need to pay to gain lifetime access or monthly, or yearly subscription
Pay in Apps – apps that are normally free, or with a free trial, but upgrading to a premium/ pro account comes with a monthly or yearly subscription fee
Pay in Apps – free apps that can be used completely free. The drawback: unless you subscribe and pay a subscription fee, you are often disturbed by audio/video/graphic banners, commercials
Phone capacitive limits:
Size of the display and screen resolution – if it allows you to see big enough to use all app functions;
Pen or stylus availability (especially for taking notes, handwriting, graphic editing);
Battery capacity (preferably over 3000mAh) or consider using an external battery;
Storage – recommended 128GB – 512 GB, available up to 2 TB or consider having the dedicated place for external micro SD for extra storage;
Characteristics to consider when searching for an app:
Refresh rate (for frequent app user or for gaming: recommended 60-120 Hz screen refresh rate);
Cameras – number of cameras: selfie camera is a must for video conferences; wide angle (up to 200MP), ultra-wide, optical zoom, digital zoom;
Waterproof, dustproof
Accessories compatibility – not all desktops, headphones, smartwatches, pens, Bluetooth devices can be connected to all types of smartphones. Compatibility may vary due to the generation of the same type of device
Connectivity – 2,4 G, 5G, 6G – relevant for communication and internet reception and quality etc.