Tokyo home roof & exterior work – advice needed

I’m planning exterior renovation work on a 25+ year old home in the Tokyo area, originally built by Mitsui Home.

Scope:

• New roof
• Exterior painting
• Weatherproofing / minor exterior repairs
• Balcony waterproofing (2)
• Termite treatment

I’ve received one quote so far (~¥7M total tax inclusive; ~40% for the roof). In the U.S., I was advised to get 5–6 quotes, but I’m unsure what’s typical in Japan.

Questions:

1. Does it matter if I get quotes from other builders (e.g., Daiwa House or independent contractors), or is it better to stick with the original builder?
2. Any vendor recommendations in the Tokyo area?
3. Is getting multiple quotes standard practice here?

Thanks in advance for any advice or experiences.